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The Availability Digest Article Archive


All of the articles which have appeared in the Availability Digest are provided here. Just click on the category in which you are interested and browse the selection. The volume and issue, if any, of the Availability Digest in which the article appeared is noted just after the title as (volume, issue) (e.g., 1,3 for Volume 1, Issue 3).


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Case StudiesNever AgainBest PracticesAvailability TopicsReadingProduct ReviewsGeek Corner




  Case Studies 

Active/Active Payment Processing at Swedbank  (3,1)  Swedbank uses active/active Base24 to support credit cards and POS terminals.

agileTel Runs Active/Active with Linux and MySQL  (8,10)  Two data centers for VoIP are kept synchronized with Tungsten data replication.

Amazon S3 Storage Taken Down by Fat Finger  (12,3)  A command to remove a small number of servers was erroneously entered.

Apollo 11 - Continuous Availability, 1960s Style  (4,9)  NASA's safety-critical computer systems put men on the moon four decades ago.

Asymmetric Active/Active at  Banco de Credito  (2,11)  Using an symmetric configuration saves programming changes. 

Bank Chooses "Sizzling-Hot-Takeover" Data Replication for its BASE24 Business Continuity Solution  (11,4)  BoV uses Shadowbase.

Bank-Verlag - the Active/Active Pioneer  (1,3)  Bank-Verlag went active/active two decades ago with IBM/Tandem. 

Bank-Verlag - An Update  (5,8)  Bank-Verlag replicates processed transactions in its active/active system.

BANKSERV Goes Active/Active  (2,4)  A banking switching service in South Africa moves Base24 into active/active.

Banks Use Synchronous Replication for Zero RPO  (5,2)  Triplexed data centers give fast recovery time with zero data loss.

Can Applications Achieve Seven Nines of Availability?  (13,3)  Software can, and active/active hardware systems can. 

Casa Ley Upgrades to Active/Active OmniPayments  (8,1)  One of Mexico's largest grocery chains installs active/active financial transaction switch.

Cellular Provider Goes Active/Active for Prepaid Calls  (3,9)  NonStop active/active system keeps prepaid calls moving in Africa.

Commerzbank Survives 9/11 with OpenVMS Clusters  (4,7)  With an active/active backup 30 miles away, getting their people there did it.

Community College Learns From SAN Disaster  (2,2)  A disastrous SAN failure leads to dual redundancy.

Controlling Amtrak Trains in the Northeast Corridor  (11,11)  The Amtrak train control system used Tandems and was developed by SAI.

CPA at Aqueduct, Belmont, and Saratoga  (2,1)  Race track wagering can never fail, or else riots start.

Do You Know Where Your Train Is?  (1,1)  A transit authority goes active/active for train tracking.

Dr. Timothy Chou Keynote Speaker at 2016 NSTBC on the Internet of Things  (12,2)  His talk focused on things that are the backbone of the planet.

European Bank's Active/Active ATM Network  (4,6)   In this active/active system, ATM failover via DNS rerouting has its problems.

Faster Payments - Bringing Payment Processing Into the 21st Century  (5,6)  VocaLink uses active/active to provide 24x7 real-time payments.

Going Prices for Personal Information  (9,1)  Did you know that your date of birth is worth $11 to hackers?

Google and Symantec Spar Over Digital Certificates  (12,4)  Google looses faith in Symantec over the issuance of improper digital certificates.

Grocery Store Chain Achieves Continuous Availability with OmniReplicator  (10,1)  Running Active/Active ensures operation during server failures.

Handelsbanken Turns to Parallel Sysplex  (4,10)  Sweden's Handelsbanken goes active/active to protect its online banking and ATM network.

High Availability, 1970s Style  (11,10)  MiniData Services, a small payroll processor, used dual processors back in the 70s to ensure continued operation.

Hospitals Under Ransomware Attacks  (11,7)  Hospitals are paying thousands of dollars to gain access to maliciously encrypted files.

How Does Google Do It?  (3,2)  Google processes tens of gigabytes of data in minutes on their massive clusters.

How Does Google Do It (part 2)  (7,11)  Google exposes how it distributes massive applications across thousands of servers while saving energy.

How the Ukraine Power Grid Was Hacked  (11,3)  Hackers disabled power for 230,000 Ukrainian customers for six hours in December 2015.

HP's Active/Active Home Location Register  (1,2)   The brains of a cellular network can never go down.

HP's OpenCall INS Goes Active/Active  (2,6)  Replication lets OpenCall INS run active/active with collision detection and resolution.

HPE Spins Off Software Assets to Micro Focus  (11,9)  HPE spin-merges its non-core software assets to Micro Focus.

Large Hadron Collider Running Out of Disk  (11,10)  The LHC has been more reliable than estimated, doubling its generation of data.

Lloyds Banking Group Outage - A Correction (12,01)  The 2014 Lloyd's Bank outage was caused by multiple CPU failures in a NonStop system.

Major Bank Uses Active/Active to Avoid Hurricanes  (2,10)  Fast failover is used to switch users out of hurricane path.

Major ISP Migrates from Sybase to NonStop with No Downtime  (3,11)  Hundreds of millions of accounts migrated and verified.

Major U.S. Bank Replaces BASE24  (7,6)  Opsol's OmniPayments keeps bank's NonStop systems running after ACI's sunset announcement.

Payment Authorization - A Journey from DR to Active/Active   (2,12)  A start with DR leads this company to active/active and application integration.

QEI Provides Active/Active SCADA with OpenVMS  (2,9)  Electrical substation monitoring that never goes down. 

RBS - A Poster Child for Outages  (11,1)  RBS and its associated banks, NatWest and Ulster Bank, have had six outages in the last three and a half years.

Real-Time Fraud Detection  (4,12)  Credit-card switching service catches fraud on-the-fly - a great example of real-time business information.

Ring-of-Fire Bank Beats Earthquakes with Active/Active  (7,7)  Moving from tape backup to active/active can be a series of controlled steps.

Royal Bank of Canada Goes Active/Active for ATM/POS  (6,7)  Eliminates planned outages and reduces unplanned downtime from hours to minutes.

Stock Exchange Speeds Clearing with Data Replication  (9,6)  Manual entry of trades is eliminated to provide same-day clearing.

Tackling Switchover Times  (1,1)  If active/active is too big a step to take now, work on reducing your switchover times.

The Bogus Missile Launch  (13,1)  Hawaiian residents received a warning that a missile was headed their way.  False alarm.

The End of Custom Software  (12,11)  The need for custom software has passed. Existing software packages exist for almost any need.

Telecom Italia's Active/Active Mobile Service  (2,3)  Italy's biggest cell phone network is supported by active/active.

Tour Operator Optimizes Look-to-Book Ratio  (6,8)  An asymmetric active/active system unloads query processing from the OLTP master node.

Try Doing This Today  (8,8)  In the early days of computing, we built major systems with kilobytes of memory and megahertz processor speeds.

UK National Health Service - Blood and Transplant  (3,10)   An OpenVMS split-site cluster guarantees the availability of the UK's blood supply.

U.S. Bank Critiques Active/Active  (4,5)   A NonStop active/active user shares experience and advice to those who would follow.

Wells Fargo's Pioneering Active/Active ATM Network  (5,9)  Dual networks with ATM collocation provides continuous availability.

Yahoo!'s Users Are Victims of Massive Hacks  (12,5)  Data from one and a half billion accounts have been stolen from Yahoo.


  Never Again

123-Reg Deletes Hundreds of its Hosted Websites  (11,4)   A maintenance-script error deletes virtual private servers hosting websites from its network.

160516  (11,6)  A NonStop date routine bug laid dormant for over thirty years, and then struck on May 16, 2016.

1961 - North Carolina Nuked (Almost)  (9,2)  A B-52 carrying 400-megaton hydrogen bombs disintegrates, and three out of four safety mechanisms fail.

911 Service Down for Six Hours Due to a Software Bug  (9,11) The entire state of Washington and seven other states had no 911 service.

$280 Million in Cryptocurrency Lost Due to Bug  (12,11)  The money was destroyed by bugs in a popular digital wallet service.

A Massive Attack on the U.S. Government  (10,6)  Chinese hackers steal personal information of over four-million government employees.

A Personal Failover Fault  (8,3) - A failed PC forces a system recovery during a slide presentation. Failover failed. The BCP saved the day.

Active/Active Save #1 - Coffee Pot Takes Down Node  (1,2)  When the coffee pot was plugged in - Surprise!

Amazon Christmas Present - Buy for a Pence  (10,1)  A glitch in a price-setting utility reduced many items on Amazon to one pence.

Amazon's Cloud Downed by Fat Finger  (6,5)  A maintenance technician's error takes down an entire Availability Zone for four days.

Amazon Downed by Memory Leak  (7,11) A memory leak in an innocuous program cascades into  major systems, taking down the AWS cloud for hours.

American Airlines Grounded by iPad Glitch  (10,5)  Pilots could not access charts stored on iPads and had to return to the gates.

American Eagle's Eight-Day Outage  (5,9)  Lack of recovery and failover testing takes down online sales for the $3 billion retailer for over a week.

Anthem Loses 80 Million Records to Hackers  (10,3)  Access was gained to the second largest health insurer in the U.S. by stolen credentials.

Ashley Madison Cheats Exposed  (10,8)  The identifications of those looking for an extra-marital affair are now posted for all to see.

Australia's Painful Banking Outages  (7,3)  Australia's four major banks suffer multiple outages as they upgrade their aging infrastructure.

Australia's Telstra Downed By Fat Finger  (11,3)  A human error dropped mobile and home phone services for 1.5 million customers for four hours.

Bank of England Suffers Major Outage  (10,4)  After warning British banks that their core legacy systems are not robust, BoE suffers its own outage.

BlackBerry Gets Juiced  (2,5)  Poor testing leads to no service for North American subscribers.

BlackBerry Messenger Down for Days  (6,10)  RIMs BBM texting service went down for over four days when it suffered a failover fault.

BlackBerry Takes Another Dive  (3,3)  Deja Vu. Poor testing once again leads to no North American service.

BlackBerry - OMG, it's Déjà Vue  (5,1)  BlackBerry has now accumulated seven major outages in five years, providing an availability of three 9s.

British Airways Downed by Fat Finger (12,6)  A technician turns off the UPS in a BA data center, taking the airline down for a weekend.

Cascading Software Bugs Take Down Google Compute Engine  (11,4)   Google's GCE takes a worldwide hit from three software bugs.

Commonwealth Bank of Australia - A Correction  (7,4)  We make a correction to our article entitled, "Australia's Painful Banking Outages."

Console Command Takes Down Active/Active System (1,3)  Stop applications on one node, stop other node. Oops!

Crimea Loses Power for Two Weeks  (10,12)  Ukrainian saboteurs destroy the power feeds delivering electricity to Crimea from Ukraine.

DDoS Attacks on U.S. Banks Continue  (8,2)   Islamic hactivists resume their attacks to get blasphemous video removed from the Internet,

Delta Air Lines Cancels 2,100 Flights Due to Power Outage  (11,9)  A fire in Delta's power room takes down its data center.

Do the Russians Have Your Tax Returns?  (10,8)  The tax returns of over 300,000 Americans have been stolen from an IRS web site.

Don't Wait for the Other Shoe to Drop  (2,2)  When a spare component fails, fix it fast. Don't tempt Murphy.

eBay's Slow Response to Data Hack  (9,7)  After learning that its user database had been hacked, it took eBay two weeks to send out notifications.

Facebook Suffers Self-Inflicted Outage  (10,3)  This outage was the worst Facebook outage in four years, but Facebook still has great uptime.

FedEx Exposes Details on Thousands  (13,2)  An Amazon S3 server set for public access contained passports and drivers’ licenses of customers.

Fire Knocks Out Samsung  (9,7)  Why did a fire in Samsung's backup data center take down its production data center?

Fire Suppression Suppresses WestHost for Days  (5,5)  Never test a fire suppression system by triggering it.

Fire Takes Down Atlanta Airport  (12,12)  A fire in the tunnel carrying both the primary power and the backup power feeds destroyed all power.

First Stuxnet - Now the Flame Virus  (7,6)  Deemed more serious than Stuxnet, Flame takes over PCs and listens in on conversations.

Gatwick Airport Reverts to Whiteboards (13,8)  A broken fiber cable prevented airport displays from working, forcing Gatwick to post gate departures on whiteboards.

GitLab Suffers Massive Backup Failure Due to a Fat Finger  (12,4)  A technician accidentally deleted 300 GB of data from a primary database.

Go Daddy Takes Down Millions of Web Sites  (7,9)   Any domain registered with Go Daddy was downed by a DNS network failure.

Google Troubles - A Case Study in Cloud Computing  (4,10)  Even the 900-pound Gorilla can have problems keeping its services up.

Hacked AP Tweet Crashes Markets  (8,5)  Phony AP tweet reporting that Obama was injured in an explosion crashes markets in seconds.

Haiti's Cell-Phone Network Costs Lives  (5,3)  Following Haiti's disastrous earthquake, many people couldn't call for help from beneath the rubble.

Happy Valentine's Day - But No Flowers  (10,3)  Global Payments financial-transaction network went down for a day and a half over Valentine's.

Has Gmail Become Gfail?  (4,3) Google's Gmail service has been down for hours six times over the last eight months.

Heartbleed - The Worst Vulnerability Ever  (9,4)  A flaw in OpenSSL allows hackers to get private keys, user names, and passwords.

History's Largest DDoS Attack?  (8,4)  Spam black-lister Spamhaus is taken down for days by a disgruntled spammer via a massive DDoS attack.

Hostway's Web Hosting Service Goes Down for Days  (2,9)  Small online stores offline for up to a week.

How 'Fat' Are Your Fingers?  (12,7)  Human errors have taken down many systems. Many of these outages are described herein.

How Many 9s in Amazon?  (3,7)  Even giants fall. Amazon's S3 and EC2 services and online retail store go offline for hours.

Hubble Trouble  (4,1)  A failover fault when recovering from an instrument controller failure almost loses Hubble.

Hurricane Irma Causes Massive Power Outages  (12,9)  Over half of Florida residents and most Puerto Rican residents lose power.

Hurricane Sandy  (7,12)  2012's Hurricane Sandy flooded lower Manhattan, taking out tens of thousands of web sites for weeks.

Innocuous Fault Leads to Weeks of Recovery  (3,12)  A simple disk mirror failure propagates into weeks of recovering lost data for a major bank.

Iowa Data Center Taken Down by Fire  (9,4)  The State of Iowa CIO gives a detailed description of the data-center recovery from the fire.

IRS Goof Costs U.S. Taxpayers $300m +  (2,1)  Turning off the old system before testing the new one is dumb.

ISIS Turns to Cyber Warfare  (10,4)  ISIS has opened a new front on its war with the West, hacking websites, Facebook pages, and Twitter accounts.

Islamic Hacktivists Attack U.S. Banks  (7,10)  Several banks taken down for a day in protest of YouTube video, "Innocence of Muslims."

Joyent Cloud Downed by Administrator  (9,6)  A mistyped command reboots all servers in the Joyent cloud.

JPMC Three-Day Outage Caused by Replication Corruption  (5,11)  Corruption of primary SAN by Oracle bug also takes down standby SAN.

Knight Capital Destroyed by Software Bug  (7,8)   A high-frequency trading bug costs Knight $440 million, forcing it to sell out to a consortium.

Lightning Downs Amazon - Not!  (6,9)  An Amazon European Availability Zone is taken down by hardware, software, and human faults.

London Stock Exchange PC-Trading System Down for a Day  (3,10)  Traders fume at commission loss on one of the most hectic trading days.

Malicious Apple Chargers  (8,8)  Researchers find a way to infect iPhones and iPads via the USB charging port.

Malware Attacks Apple Apps  (10,10)  Chinese developers use infected Apple utility to create apps sold in the Chinese iOS App Store.

Marketo Goes Down, Revived By Customer  (12,8)  Marketo forgot to renew its domain, but a customer renewed it for them.

Medical Center's Multiday Outage  (6,2)  An attempt to achieve high availability on a limited budget leads to non-availability.

Meltdown and Spectre Security Threats  (13,1)  These threats steal data from a CPU’s cache left there by speculative execution.

Metro-North Taken Down by Redundant Power Failures  (8,10)  The primary power cable fails while the other one is being upgraded.

Microsoft's Azure Cloud Goes Down - Again  (9,12)   A faulty upgrade and improper deployment brought down Azure for eleven hours.

Military GPS Disabled by Upgrade  (5,6)  A failed upgrade to support the next GPS generation takes down 10,000 military GPS receivers.

Mizuho Bank Down for Ten Days  (6,6)  A flood of earthquake donations by mobile phones overwhelmed the bank's evening batch runs.

More Never Agains  (3,8)   Over two dozen disastrous outages for the first half of 2008 are recounted.

More Never Agains II  (4,2)  System downtime problems have moved from the power lines to the networks.

More Never Agains III  (4,7)  Add the cloud to power and network problems creating over two dozens outages on which we report.

More Never Agains IV  (5,2)   Network, hardware/software problems highlight outages for the last half of 2009.

More Never Agains V  (5,7)   Over half of our 30 horror stories took down hosting providers. A failover plan is a must.

More Never Agains VI  (7,4)  Software bugs and recovery faults highlighted the outages in the first quarter of 2012.

More Never Agains VII  (7,9)  Power outages were the main cause of these failures.

More Never Agains VIII  (8,2)  Security threats are becoming more prevalent, with the Chinese evidently leading the charge.

More Never Agains IX  (8,7)  Environmental faults lead the list, followed by updates gone awry.

Mt. Gox, Largest Bitcoin Exchange, Goes Belly Up  (9,3)  Hackers steal 855,000 bitcoins worth over $500 million, forcing Mt. Gox into bankruptcy.

Nasdaq Taken Down by Software Flaw  (8,9)  A blast of messages from the NYSE disables Nasdaq's quote reporting system and causes a failover fault.

National Australia Bank Customers Down for Days  (5,12)  A bad batch update disables critical customer services for two weeks.

Network Crashes  (12,10)  Networks have not always been as robust as they are now. ARPANET had several failures in the late 1900s.

New York City's New 911 System Goes Down Four Times  (8,6)  After extensive testing, the city lost 911 service four times in two days.

Northern Virginia's 911 Service Down for Four Days  (7,12)  90 mph winds and air in the generator's fuel lines takes down a Verizon 911 hub.

On-Demand Software Utility Hits Availability Bump  (2,10)  A utility is expected to be always up, but this one didn't make it.

Our Power Grid Must Be Reliable and Resilient  (12,9)  Reliable power is power without interruption. Resilient power is quick restoration of power.

Oracle's Ticking Time Bomb  (7,2)  An obscure bug in the Oracle database could take down an entire data center if not patched immediately.

Orca - The Outage That May Change History  (7,11)  The Republican 2012 Get-Out-The-Vote system flopped from the beginning.

PayPal Fault Takes Merchants Offline  (4,9)  A network fault forces small online merchants to close shop for hours.

Poor Documentation Snags Google  (5,4)  A data center goes down, and failover to the backup data center goes awry.

Pop! Goes the Weasel!  (11,6)  A weasel gnaws through a high voltage line and takes down the CERN Large Hadron Collider.

Rackspace - Another Hosting Service Bites the Dust  (2,12)  A truck driver wipes out web sites for a day or more.

Royal Bank of Scotland Offline for Two Weeks  (7,7)  Falling back from a failed upgrade failed and took three U.K. banks down.

Royal Bank of Scotland Suffers Multiple Outages  (8,12)  RBS, NatWest, and Ulster fail three times in eighteen months due to aging systems.

RushCards Deny Funds to the Unbanked (10,11)  Prepaid debit cards upon which may depend went inactive for ten days due to a technical glitch.

Salesforce Takes a Dive  (11.7)  A hardware bug followed by a firmware bug takes Salesforce down for six days.

Shellshock - The Bash Vulnerability  (9,10)  A critical code-injection vulnerability has been discovered in the popular Bash shell

Sidekick: Your Data is in 'Danger'  (4,11)  A million smart-phone users lose all of their contacts, calendars, and photos.

Singapore Bank Downed by IBM Error  (5,8)  An undocumented new procedure takes down all DBS Bank systems for hours.

Skype Holiday Present - Down for a Day  (6,1)  Skype overload takes down its peer-to-peer network of hundreds of thousands of supernodes.

So You Think Your System is Robust?  (2,8)  So did these major enterprises, all of which went down in the first six months of 2007.

So You Think Your System is Reliable  (3,1)  Horror stories from the second half of 2007 focus on power and branch failures.

Software Bug Causes Train Wreck  (1,1)  A software bug, controller diversion, and engineer inattention combine to cause a train collision.

Sony PlayStation Taken Down for Weeks by Hackers  (6,5)  Hackers steal 100 million accounts from Sony, requiring weeks to repair security defenses.

Southwest Airlines' Router Grounds 2,300 Flights  (11,8)  A router failed in an unusual way, and the outage was not recognized by its backup.

Spamhaus Attacker Caught  (8,5) The mastermind behind the ten-day 300 gbps attack on Spamhaus arrested in Spain and extradited to The Netherlands.

Stuxnet - The World's First Cyberweapon  (6,3)  Stuxnet is the first worm to attack a control system and destroy machinery.

Sydney's M5 Tunnel Closed Again by Computer Glitch  (3,11)  Six times in six years is too much for New South Wales.

Target Compromises Millions of Payment Cards  (9,1)  The magnetic stripe data on payment cards is stolen from 40  (updated to 110) million cards.

The $45 Million ATM Heist  (8,5)  Hackers clone prepaid debit cards and net $45 million in ten hours from ATMs around the world.

The Alaska Permanent Fund and the $38 Billion Keystroke  (2,4)  What do you do when your active and backup disks are wiped out and your tapes won't read?

The Case of the Flying Cable  (1,1)  A technician loses control of an under-floor cable and lets it hit a power strip.

The FAA's Availability Woes  (4,12)  Application and network failures plague air travelers. Where is NextGen - the next generation airspace system?

The Government OPM Hack Gets Worse  (10,7)  OPM now acknowledges that personal information belonging to 20 million Americans was stolen.

The Great 2003 Northeast Blackout and the $6 Billion Software Bug (2,3)  A hot day, an untrimmed tree, and a monitoring system bug cost power customers $6 billion.

The Internet Hits a Capacity Limit  (9,8)  Verizon exceeds an address limitation in the Border Gateway Protocol and slows the Internet to a crawl.

The Planet Blows Up  (3,9)  A massive electrical eWannaxplosion takes out thousands of hosting servers at a major dedicated hosting provider.

The State of Virginia - Down for Days  (5,10)  A maintenance error takes down 26 state agencies for up to a week.

TWC Internet Outage Affects Millions  (9,9)  A human error by the U.S.'s second largest cable provider disables its Internet service for hours.

Twitter Taken Down by DDoS Attack  (4,8)  The Twitter, Facebook, and LiveJournal social sites are taken down to silence a Georgian blogger.

Triple Redundancy Failure on the Space Station  (2,11)  A single point of failure takes down a triplexed critical computer.

U-2 Spy Plane Crashes FAA Computer  (9,5)  Overflying Los Angeles at 60,000 feet, a U-2 wreaks havoc on air traffic in the U.S. Southwest.

U.S. Internet Traffic Comes to a Halt  (11,11)  A DDoS attack on a major DNS server prevents access to web sites.

Verizon 4G Network Down for Two Days  (6,6)  Verizon's "always reliable" 4G network brought down by software bug - no 3G backup.

Verizon Cloud Down for Forty Hours  (10,2)  Verizon takes its cloud down for two days to install a zero-downtime upgrades.

VMware's Cloud Foundry Flounders  (6,7)  A storage fault caused by a power outage is followed by a bigger fault caused by a fat finger.

Vodafone Downed by Burglars  (6,4)  Thieves sledgehammer their way into a Vodafone exchange and steal computers and network equipment.

VoIP PBX Succumbs to Overconfiguration  (2,6)  Why extra processing power made this PBX less reliable.

WannaCry Ransomware Global Attack  (12,6)  WannaCry malware infects Windows 7 machines, encrypts files, demands $300 ransom.

What? No Internet?  (3,2)  A multiple cable break isolates North Africa, the Middle East, and India.

What if GPS Fails?  (12,1) GPS can fail for a number of reasons. A failure would be anything from an inconvenience to a catastrophe for many.

Why Back Up?  (4,4)   The malicious act of an IT manager deletes his company's database and forces the company to close its doors.

Will You Have Internet Access After July 9, 2012?  (7,5)  A recent FBI sting took down rogue DNS servers and substituted good servers until July 9th.

Windows Azure Cloud Succumbs to Leap Year  (7,3)  As the clock ticked to February 29th, the Azure Cloud went down for 32 hours.

Windows Azure Downed by a Single Point of Failure  (8,11)  Azure developers could not run new applications after a failed Microsoft update.

  Best Practices

2010 NonStop Availability Award  (5,10)  This year's winner is Bank-Verlag with runners up Belgacom and VocaLink.

2013 NonStop Advanced Technical Bootcamp  (8,9)  To be held in San Jose in November, the NonStop Bootcamp is the premier NonStop annual meeting.

2014 HP NonStop Technical Boot Camp  (9,10)  The 2014 NonStop Boot Camp will be held in San Jose from November 16th through November 19th.

2015 - The Year of the Leap Second  (10,2)  One second will be added at midnight, June 30th, potentially bringing down many systems.

911 Systems Experience Unacceptable Availability  (9,3)  Statistics show that the availability of 911 systems is, at best, dismal.

Accounting for Non-Accountants  (12,4)  Explaining the double-entry book-keeping system to software engineers.

Achieving Fast Failover in Active/Active Systems - Part 1  (4,8) Using user and network redirection to failover in subseconds.

Achieving Fast Failover in Active/Active Systems - Part 2  (4,9)  Using server redirection to failover in subseconds.

Active/Active Data Centers  (8,12)  Entire data centers are now going active/active with instant reliable failover.

Adding High Availability to the Cloud  (9,8)  Critical applications on internal servers, other applications in the cloud with data replication.

Applying Predictive Analytics to Power Backup  (10,12)  Predictive analytics can forecast UPS and generator failures for proactive maintenance.

Availability Best Practices  (2,1)  Tips from those who have achieved near-continuous availability.    

Avoiding Capacity Exhaustion  (7,7)   A strikingly simple graphic display forecasts capacity peaks by the hour over the year.

Avoiding Notworks  (4,1)  A network that doesn't work in a "notwork." Protect your network with a good SLA.

Backup Is More Than Backing Up  (4,5)   Backing up a database is an exercise in futility if you can't restore the database.

Boeing 787 Could Lose All Power  (10,6)  A software bug in the generator control units could cause pilots to lose control of the 787 Dreamliner.

Build to Fail  (9,11)  NetFlix survived an Amazon reboot by proactively ensuring that its applications would continue to work under any failure.

California Fires Destroy HP Archives  (12,11)  An archive of historic documents created by Hewlett and Packard destroyed by fire in Sonoma County.

Can 10,000 Chickens Replace Your Tractor?  (1,3) Save money by replacing your mainframe with clusters - Not!

Can a Country Shut Down Its Internet?  (11,10)  Some countries only have one or two ISPs, and have on occasion shut down their Internet access.

Can You Trust the Compute Cloud?  (3,8)  What will it take to make cloud computing the data utility of the future?

Chillerless Data Centers  (4,11)  Google and Yahoo! locate new data centers in the north country to take advantage of "free cooling."

Choosing a Business Continuity Solution - Part 1  (6,7)  What measures of availability are important to your organization?

Choosing a Business Continuity Solution - Part 2  (6,8)  Data replication is the fundamental force behind system availability.

Choosing a Business Continuity Solution - Part 3  (6,9)  Data replication leads to several highly available architectures.

Choosing a Business Continuity Solution - Part 4  (6,10)  Choosing a highly available architecture to meet your availability needs.

Cloud-to-Cloud Backup  (13,2)  Application data stored in a cloud can be backed up in another cloud.

Continuous Availability Featured at HPTF 2009  (4,6)  Presentations include many continuous availability and high availability talks.

CryptoLocker - Destructive Ransomware  (8,11)  CryptoLocker encrypts your files until you pay a ransom.

Cyber Threats Surpass Terrorism  (8.3)  The U.S. government says that in 2013, cyber threats surpassed terrorism as the top security concern.

Dark DR - Avoid its Costs With Active/Active  (12,8)  The passive side of an active/passive redundant system is 'dark' - it is doing no work.

Data Centers Consume Inordinate Amounts of Energy  (11,8)  Data centers are among the fastest growing users of electricity.

Data Center Cooling Nature's Way  (5,5)  Data centers cut electric bills in half by replacing chillers with air economizers.

Data Center in a Box  (4,7)  Your next visit to a data center may be to the warehouse district.

Data Center Monitoring with Open-Source Nagios  (6,11)  Including NonStop systems in open-source "single pane of glass" monitoring.

Data Deduplication  (6,2)  Data deduplication can reduce backup storage and disaster-recovery bandwidth requirements by a factor of 20:1.

Data Deduplication in the Cloud  (13,3)  As the cloud becomes used more for data storage, deduplication in the cloud becomes more important.

DDoS Attacks on the Rise  (8,4)  2012 saw a 53% rise in DDoS attacks with greatly increased malicious bandwidth.

Department of Homeland Security: Disable Java  (8,2)  A serious vulnerability in Java 7 means that it should be removed from browsers.

Digest Managing Editor Speaks About Staggered Systems  (11,12) Dr. Bill speaks at the 2016 NonStop Technical Boot Camp.

Document Your System  (1,2) Documentation is a necessary evil. Let's focus on the "necessary" and not the "evil."

Does Data Replication Eliminate the Need for Backups?  (5,11)  Data replication protects operations; data backup protects data.

DRJ's Fall World 2010 Business Continuity Conference  (5,8)  A week-long conference in September, 2010, focusing on Business Continuity.

DRJ's Spring World 2011 Business Continuity Conference  (6,2)  A week-long conference in March, 2011, focusing on Business Continuity.

DRJ's Fall World 2011 Business Continuity Conference  (6,8)  A week-long conference in September, 2011, focusing on Business Continuity.

DRJ's Spring World 2012 Business Continuity Conference  (7,1)  A week-long conference in March, 2012, focusing on Business Continuity.

Enterprise Availability Architectures for Business-Critical Services  (8,6)  Achieving the proper balance of availability and cost.

Equifax Hacked for Data on 143 Million Customers  (12,9)  This was one of the largest breaches of consumer data in history.

Facebook Turns Off an Entire Data Center to Test Resiliency  (11,11)  Perhaps the ultimate in disaster recovery testing.

FBI Warns Employees Are New Targets  (7,11)  The FBI warns that cybercriminals are moving from corporate IT systems to corporate employees.

Flywheel UPS Systems  (9,1)  Flywheel UPS systems have many advantages over battery UPS systems.

Future Dates Spell Problems for IT  (12,3)  Date/time integers roll over in 2038 and in 2042.

Google's Extreme-Green Data Centers  (3,12)  Wave motion and seawater may power and cool data centers in the future.

Handling Data Collisions in Asynchronous Replication  (5,9)  An update on data collision avoidance, detection, and resolution.

High Availability Topics at HP Discover 2011  (6,5)  Over two dozen presentations on high-availability topics will be presented in Las Vegas in June, 2011.

High-Voltage Transformers - The Power Grid's Achilles Heel  (11,3)  A major catastrophe can knock out large transformers in our power grid.

How Can Data Centers Manage a Drought?  (10,5)  California's four-year drought brings datacenter water usage to the forefront.

How Do Your Readiness Plans Stack Up?  (6,1)  Compare your disaster recovery plans with those of 300 other companies.

HP CloudSystem  (7,2)  Companies can convert their current IT assets into a private cloud that can burst into public clouds.

HP Discover 2011  (6,3)  HP Discover 2011 is HP's major annual marketing and educational event, held in Las Vegas June 6th to June 10th, 2011.

HP's Project Odyssey - Migrating Mission Critical to x86  (7,3)  HP is moving HP-UX high availability features to Intel's Xeon x86 chip.

HP Blows Up Data Center  (2,8) An explosive demonstration of fast recovery.

HP's Cloud Recovery-as-a-Service  (7,6)  HP's cloud-based recovery service provides fast RTOs and short RPOs with no upfront capital expenditures.

Human Triple Whammy - NYSE, UA, WSJ  (10,7)  70% of system outages involve a human error to some extent. Humans need redundancy too.

Humanizing Three 9s  (2,9)  What if we lived in a world of three 9s?

IBM Builds Super-Dense 5-Nanometer Chip  (12,7)  With transistors packed more closely, the chip achieves a 40% boost in performance.

IE Vulnerability Allows Remote Code Execution  (9,5)  A zero-day Internet Explorer vulnerability allows attackers to take over your systems.

ING Bank Bown Ten Hours Due to Fire-Suppression Test  (11,9)  The noise from the test of its fire suppression system damages hard disks.

Interview with Ron LaPedis on NonStop with XP Storage  (2,5)  How to improve NonStop reliability by using a SAN.

IPv6 Is Here - Like It or Not  (6,4)  Some tips from a father of the Internet on the simple ways to convert from IPv4 to IPv6.

Is Preventive Maintenance Preventive?  (7,10)  Major IT faults have been caused by preventive maintenance errors. Is PM worth it?

ISO 22301 - The New Business Continuity Management Standard  (7,10)  The first business continuity specification to be issued by ISO.

Japan's Data Centers Survive Their Big One  (10,10) What lessons can we learn from how Japan's data centers survived the great earthquake?

Katrina - The Harsh Teacher  (2,6)  The most powerful Gulf storm in 200 years showed us how unprepared we were for such a disaster.

Keylogger Found on HP Laptops  (12,12)  A tool to log all keystrokes is in the Synaptics touchpad driver on hundreds of models of HP laptops.

Let's Share Outage Information for the Benefit of All  (9,4)  We can learn a great deal from the experience of others to resolve system outages.

Load Shedding  (7,12)  If your system begins to overload, how do you determine what load to shed?

Magnetic Tape Makes a Comeback  (12,10)  With so much data being created by mobile devices and sensors, magnetic tape is returning as viable storage.

Malware as a Service  (6,12)  Powerful hacking software is becoming just a click away.

Managing Your Private Cloud  (10,4)  A cloud needs constant managing as its application grow and as application mix changes

Maximizing Availability in Everyday Systems  (5,7)   Even if you don't have a redundant system, there are things you can do to minimize outages.

Microrebooting for Fast Recovery (2,3)  An application of Recovery-Oriented Computing.

Migrating IBM Power System to HPE Open Systems  (11,5)  Moving applications from Power Systems to open systems can save up to 50%

Mobile Device Threats to Corporate Networks  (8,7)  Mobile devices are a convenience for employees but a security threat for corporations.

Multifactor Authentication  (10,9)  Passwords can be stolen. Add another identification factor to improve your security.

NonStop Boot Camp is Coming in October  (7,8)  The NonStop Community will gather in San Jose from October 14th through October 16th, 2012.

On Blogs and Discussion Groups  (2,10) Online forums can be a big boost to your professional growth.

Openness Was Not Always Assured  (13,3)  Years ago, systems were not open and could not interoperate.

OpenStack - The Open Cloud  (7,4)  A major open-source initiative may take us one step closer to a true worldwide compute utility.

OpenVMS Boot Camp Is Coming in March  (8,2)  It will be held for four days from March 18th through March 21 in Bedford, Massachusetts.

Oracle Releases Massive Security Patch for Java  (8,5)  Following DHS recommendation to disable Java, Oracle releases 42 critical security updates.

Protect Your Data Center From Flooding  (11,1)  Sea levels are rising. Now is the time to concern yourself with protecting your data center.

Protecting Big Data - Erasure Coding  (10,11)  Erasure coding can protect thousands of disks with only an efficient few.

Recovery-Oriented Computing  (2,2)  If recovery time can be made small enough, users will perceive a faultless system.

Reliable Multicasting  (3,1)  How to get messages over LAN and WAN multicast networks without message loss.

Retail Web Sites Losing Millions to Poor Response Time  (7,1)  Slowness is worse than downtime - it makes people hate your site.

Roll-Your-Own Replication Engine - Part 1  (5,1)  What does it take to build your own replication engine? Lots!

Roll-Your-Own Replication Engines - Part 2  (5,2)  Issues with asynchronous and synchronous replication engines.

Rules of Availability - Part 1  (3,3)  The first set of common rules of availability from our books, Breaking the Availability Barrier.

Rules of Availability - Part 2  (3,5)  More common rules of availability from our books, Breaking the Availability Barrier.

Rules of Availability - Part 3  (3,7)  Concluding the common rules of availability from our books, Breaking the Availability Barrier.

Saving Data Centers by Creating Chaos  (13,2)  Enterprises are breaking their systems on purpose to smoke out weaknesses.

Serverless Computing  (13,1)  Allows one to build and run applications without thinking about servers. It’s all handled by the cloud.

Should Hope Trump Failover?  (9,2)  Too often, the decision to failover is delayed because failover is more risky than trying to recover the production system.

Software Documentation  (11,2)  The Waterfall method of heavy documentation has given way to Agile software methodology with minimum documentation.

Swapping Data Replication Engines with Zero Downtime  (12,12)  A replication engine can be upgraded or changed without an outage.

Superstorm Sandy Survivors  (8,6)  How three companies in the path of Sandy kept their systems and services operational.

Synchronous Replication Recovery Strategies  (5,3)  Bringing a failed database copy back on line under synchronous replication.

Telstra Plague With Series of Outages  (11,6) Australia's major telecommunication company had several outages in early 2016.

The 25 Most Exploitable Programming Errors  (8,2)  A detailed list of the programming errors that expose the most vulnerable security holes.

The Big One - Are You Ready?  (10,9)  The Cascadia Subduction Zone is about to unleash the mother of all earthquakes in the Pacific Northwest.

The Importance of Failover Testing  (12,7)  If you don't test your failover procedures, your backup may not come up when you need it.

The Looming Threat of a Solar Superstorm  (11,7)  A solar superstorm that could take power out for months is overdue.

The Smarts Behind EMV Smart Cards: Part 1 - Online Processing  (9,11)  Smart cards are finally coming to the U.S. How do they work?

The Smarts Behind EMV Smart Cards: Part 2 - Offline Processing  (9,12)  Authorizing smart card transactions offline.

The Value of Availability  (6,6)  Downtime costs are based on the likelihood, duration, impact, and cost  of each risk factor taken individually.

The Zero Outage Industry Standard Organization  (12,2)  ZOISA focuses on minimizing the risk of IT outages.

Transaction-Oriented Computing  (2,4) Old art to some, new to others, transaction processing is the foundation for high availability.

Twitter Earthquake Detector  (5,4)  The U.S. Geological Service is mining tweets to get instant notification of earthquakes.

Using Dark Fiber  (13,8)  Fiber optic networks provide high bandwidth, scalability, high availability, near-zero latency, and enhanced security.

VRRP - Virtual Router Redundancy Protocol  (3,10)  Adding transparent failure detection and failover at the first hop.

What Really Caused the Windows Azure Outage?  (7,5)  The Windows Azure cloud was taken down by a simple leap-year bug.

Why Your Business Continuity Plan May Be Inadequate  (9,9)  Is your business plan satisfactory, well-tested, and well-supported?

Windows Server 2003 Nearing End-of-Life  (9,7) Microsoft will terminate support for Windows Server 2003 in July, 2015.

Windows XP is No Longer PCI Compliant  (9,6)  With no security patches forthcoming, Windows XP systems are no longer compliant with PCI DSS.

Windows XP Retirement a Hackers' Boon  (8,10)  Hackers are holding zero-day attacks until Microsoft no longer provides security fixes.

With 100% Uptime, Do I Need a Business Continuity Plan?  (1,1)  You'd better believe it.

Yahoo Hack Sets a Record - 500 Million Accounts  (11,9)  Details from a half-billion customer accounts were stolen from the Yahoo database.

  Availability Topics

911 Systems Are Failing Too Often  (11,5)  Though 911 systems should be considered highly mission-critical, they fail all too often.

Active/Active Full Day Seminar at HPTF  (4,4) Dr. Bill speaks on active/active theory and practice at the 2009 HPTF conference.

Active/Active on Commodity Servers  (8,9)  Why has active/active technology not made it into the commodity server world?

Active/Active Versus Clusters  (2,5)  For high availability, clusters are mature; but active/active systems provide greater reliability.

Active/Active Systems - A Taxonomy  (3,9)  Classifying the many ways to build an active/active system.

Adding Availability to Performance Benchmarks  (2,9)  Recovery time is the proper metric to use for an availability benchmark.

Airlines' Aging Technology Is Taking Its Toll  (11,10)  Outdated IT systems can strand thousands of passengers and cost airlines millions of dollars.

Airline Outages Continue to Ground Passengers  (12,3)  Airline systems are based on old technology and are prone to failure.

Amazon's Availability Zones  (6,11)  Critical applications can run reliably in the cloud by distributing them across Amazon Availability Zones.

All About Continuous Processing Architectures  (1,1)  CPA can get you arbitrarily close to 100% uptime.

Anatomy of a DDoS Attack  (8,4)  DDoS attacks take down web sites by aiming traffic at various levels in the Internet protocol.

Anti-Virus - A Single Point of Failure?  (5,5)  McAfee's malicious anti-virus update takes down millions of computers in a flash.

Are Our Power Grids Vulnerable?  (8,12)  The danger weather of bringing down our power grids is being compounded by the danger of terrorism.

Asynchronous Replication Engines  (1,2) These engines power most of today's active/active systems.

Availability in the Cloud  (13,1)  The cloud embodies the ides of anywhere and anytime access to service, tools, and data.

Availability Organizations  (10,10)  Many of the organizations that offer availability advice and services are reviewed.

Availability versus Performance  (2,8) Is it time to trade higher availability for reduced performance?

Banks Worldwide Suffer from IT Legacy  (9,2)  Reliance on decades-old applications are causing a rash of banking outages.

Can Hackers Take Down Our Power Grid?  (11,1)  Ukraine lost much of its power in December, 2015. Are other countries at risk?

Can You Trust Your Public Cloud?  (9,6)  With a history of massive failures, public clouds require extra care for critical applications.

Can An Airliner Be Hacked?  (10,5)  Airliner avionics are often connected to the same Intranet as the passenger in-flight entertainment systems.

Choosing a Database of Record  (3,11)  Which database copy in an active/active network is the "single version of truth?"

Cloud Resiliency  (12,12)  Cloud computing has dramatically changed they way we think about application resiliency.

Collision Detection and Resolution  (2,4)  What do you do if you can't avoid collisions when using bidirectional replication?

Comparing Clouds with CloudHarmony  (10,1)  Amazon, Google win with five 9s; Azure, CenturyLink lose with three 9s.

Court Decides - HP 1, Oracle 0  (7,8)  Judge finds Oracle arguments a Seinfeld sitcom, orders continued Oracle support of HP Itanium servers.

Cyber Security and Downtime  (11,5)  Various forms of malware can take down your application.

Defining Active/Active  (4,12)  Can we agree on what are active/active architectures? Add your comments to this ongoing effort.

Defining Active/Active - Revision 1  (5,1)  Revision 1 of our definition based on suggestions posted to our LinkedIn Continuous Availability Forum.

Eavesdropping on the Internet  (4,3)  A vulnerability in the Border Gateway Protocol allows nefarious sites to read your Internet traffic.

Eliminate Those Single Points of Failure  (12,10)  In order for a system to be highly available, all components must be redundant.

Epidemic of Certificate-Related Outages  (4,2)  Organizations are letting their digital certificates expire, thus losing access to public encryption keys.

Failsafe  (11,8)  Failsafe makes the point that sometimes software lies.

Fault Tolerance for Virtual Environments - Part 1  (3,3)  How virtualization can significantly reduce data center capital and operating costs.

Fault Tolerance for Virtual Environments - Part 2  (3,4)  Operating system and bare metal hypervisors.  

Fault Tolerance for Virtual Environments - Part 3  (3,6)  Hardening virtual environments with failover and fault-tolerance.

Fire Extinguishers Can Cause Data Center Outages  (12,11)  The noise of the sirens can be loud enough to damage hard disks.

Fire Suppressant's Impact on Hard Disks  (6,2)  Fire alarm sirens in the data center are fingered as the culprit in hard-disk damage.

Fog Computing Improves Application Availability  (12,6)  By distributing critical processing to cloudlets, cloud outages can be masked.

FS-ISAC: Financial Services - Information Sharing & Analysis Center  (7,10)  A member-owned industry forum for sharing security threats.

Hardware Replication  (2,1)  Replicating at the hardware level does not maintain database consistency.

Heartbleed Attacks Androids  (9,5)  Heartbleed flaw in Android apps leaves millions of Androids vulnerable to data loss.

Help! My Data Center is Down! - Part 1: Power Outages  (6,10)  Unusual data center outages caused by power failures.

Help! My Data Center is Down! - Part 2: Storage Outages  (6,11)  Unusual data center outages caused by storage system failures.

Help! My Data Center is Down! - Part 3: Internet Outages  (6,12) Unusual data center outages caused by Internet failures.

Help! My Data Center is Down! - Part 4: Intranet Outages  (7,1) Unusual data center outages caused by intranet failures.

Help! My Data Center is Down! - Part 5: Upgrades  (7,2)  Unusual data center outages caused by upgrades gone wrong.

Help! My Data Center is Down! - Part 6: The Human Factor  (7,3)  Unusual data center outages caused by fat fingers.

Help! My Data Center is Down! - Part 7: Lessons Learned  (7,4) The lessons we can learn from the data center failures of Parts 1 to 6.

How Does Failover Affect Your SLA?  (9,12)  Recovering to a backup system takes time and reduces availability.

How HPE Is Making Blockchain Resilient  (12,7)  HPE is porting blockchain to its NonStop servers to provide continuous uptime.

HP Clarifies the Future of OpenVMS  (8,7)  OpenVMS will be supported by HP for years to come.

Hurricane Harvey's Hit on Houston Spurs NextGen 911  (12,9)  After Houston flooded, 911 service was overloaded. NextGen 911 is needed.

Hypoxic Fire-Prevention Systems  (6,1)  Why drown your servers after a fire breaks out? Keep the fire from starting in the first place.

Improving Power Availability with Microgrids  (11,11)  A microgrid can disconnect from the main electric grid to keep power flowing..

Is the Cost of Converting to Active/Active Worth It?  (4,11)  Offsetting the cost of conversion with the cost of downtime.

It's Official! Leap Day Caused the Windows Azure Outage  (7,5)  Incrementing the year by one to get next year's date took down the Azure cloud.

Jim Gray - In Memoriam  (3,7)  The database pioneer that set the stage for active/active systems is lost at sea.

Leslie Lamport Wins Turing Award for Distributed Computing  (9,3)  Lamport contributed to the theory and practice of concurrent distributed systems.

Let's Get an Availability Benchmark  (2,6)  Great performance is meaningless if the system in unavailable.

Leveraging Virtualization for Availability  (5,12)  With many eggs in one basket, system availability becomes all that more important.

Linux Leap-Second Bug Takes Down Data Centers  (7,8)   A leap second added on June 30, 2012, takes down unpatched Linux systems worldwide.

Media Communication During a Crisis  (6,5)  Don't create a second crisis by letting the press publish erroneous and damaging stories.

Migrating Your Application to Active/Active (2,3)  What must you do to prepare your application for an active/active environment?

My Jeep Wasn't Hacked!  (10,08)  Security researchers were able to hack into and remotely control Jeep Grand Cherokees via the infotainment system.

Napa Wildfires Wipe Out Communications  (13,8)  During a fierce windstorm, wildfires in Northern California burned over 245,000 acres.

OpenVMS Support To Continue Indefinitely  (9,8)  HP does U-turn, licenses VSI to support OpenVMS indefinitely on all future HP platforms.

Ponemon on Live Threat Analysis  (8,11)  Intelligence data about cyber threats happening right now is crucial to stopping cyberattacks.

Power Outages Caused by Animals  (11,7)  Squirrels are more of a threat to our power grid than hackers.

Recovery-as-a-Service  (8,2)  RaaS provides backup service in the cloud for critical applications.

Reducing Pharmaceutical Pollution  (8,1)  Monitoring of pharmaceutical processing practices to reduce pollution requires high availability computing.

Remembering Ken Olsen - An IT Icon  (6,3)  The founder of Digital Equipment Corp., Ken (1926 - 2011) brought interactive computing to the individual.

Should Cyber Victims Be Fined?  (12,8)  The U.K. is fining victims of cybercrime if they are an essential infrastructure operator.

Social Media Availability and Performance  (6,4)  Social media is becoming critical in our daily lives. It is time for it to grow up.

Sophos Security Threat Report 2013  (8,6)  The major security threats of 2013 for businesses and individuals.

Spamalytics  (4,10)  How good are our spam filters, and why does spam till pay?

Stratus Bets $50,000 That You Won't Be Down  (5,1)  Buy an ftServer by February 26, 2010, and Stratus will give you $50K if it fails in the first six months.

Stratus Puts $50,000 Where its Mouth Is - Again  (6,12)  Stratus' offer to pay you $50,000 if your ftServer/vSphere application fails expires 12/31/11.

Stratus Puts $50,000 Where its Mouth Is - an Update  (7,2)  Stratus extends its $50,000 ftServer/vSphere availability offer for another year to 12/31/12.

Synchronous Replication  (1,3)  Avoid data collisions and data loss following a node failure.

The Availability Matrix  (6,1)  Simplify your data center availability configurations using the independence of RTO and RPO.

The Causes of Outages  (8,3)  250 Never Again stories tell us the proportion of outages due to hardware, software, humans, networks, and other faults.

The Continuing Struggle with Legacy Systems  (11,12)  Decades old legacy systems deny enterprises flexibility.

The Darknet  (9,9)  Stolen financial credentials are sold on the Darknet, a private network with connections only between trusted peers.

The Dawn of Fault Tolerant Computing  (11,04)  In the early 1980s, there were several fault-tolerant systems. Only Tandem and Stratus survived.

The Fragile Cloud  (4,6)   This new computing paradigm might ultimately replace corporate data centers if it can ever be made reliable.

The Fragile Internet  (4,5)   Can you trust your mission-critical applications solely to the Internet? We think not.

The Future is Decentralized Data Storage  (13,2)  Decentralized storage is a model of online storage in which data is stored on multiple computers.

The History of Fault Tolerance  (1,2) The fault-tolerant marketplace was hot in 1984.

The Malware Threat to Android  (7,9)   With its major market share and unvetted apps, Android is the prime smart phone target for hackers.

The IPv4 Doomsday  (4,8)   The Internet Protocol Version 4 is about to run out of its four billion addresses in two years. What now?

The Ubiquitous Internet  (4,7)  1.5 billion users, 200 million web sites, and one-million viruses depend on the Internet

The U.S. Government's IT Fossils  (11,2)  The U.S. Government spends 75% of its IT budget on supporting legacy systems.

Time Synchronization for Distributed Systems - Part 1  (2,11)  How does NTP calculate the time offset from a time server?

Time Synchronization for Distributed Systems - Part 2  (2,12)  How NTP minimizes time offset errors?

Time Synchronization for Distributed Systems - Part 3  (3,2)  Logical clocks offer an option for synchronizing systems.

Transaction Replication  (2,2)  A simple approach to active/active systems has scalability issues.

Tussling with the Word "Redundant"  (3,12)  "Redundant" doesn't always translate the same to those in different countries.

Unintended Acceleration and EMI  (5,4)  If testing doesn't show it, does that prove that EMI can't make an engine computer misbehave?

United Airlines Bug Bounty Program  (10,7)  United Airlines is offering frequent flyers millions of miles for discovering security vulnerabilities.

Upgrades Can Take Your Down  (10,9)  Each upgrade must be carefully planned and tested. Be prepared to roll it back if it doesn't work.

Using an Availability Benchmark  (3,10)  Making use of a recovery time benchmark to influence your system choice.

VSI Releases First New Version of OpenVMS  -  (10,6)  A year after its founding, VMS Software Inc. releases OpenVMS version 8.4-1H1.

WestHost Fire Suppression Test Fiasco - An Update  (5,9)  Why did the accidental activation of the fire suppression system destroy so many disks?

What is Active/Active?  (1,1) Active/active architectures can give subsecond recovery following a failure. 

What is Reliability?  (5,6)  We can get rid of marketeering by quantifying highly-reliable computer systems by their reliability parameters.

What is Reliability?  (13,3)  An update on our earlier article.

What is the Availability Barrier?  (5,3)  Mean time to recover. Let it fail but fix it fast.

What's Your Concern - MTR or MTBF?  (5,11)  Recovery time is for users, failure intervals are for system operators, availability is for management.

Windows 7 Mainstream Support Ends  (10,2)  With mainstream support ending, Windows 7 users must upgrade to Windows 10, a free upgrade for a year.

Worsing on Worsening  (4,2)  A 1967 chewing-out of IBM's Field Service staff resounds still today.

  Recommended Reading

2014 Verizon Data Breach Investigations Report  (9,9)  Most security incidents can be categorized into nine categories.

2015 Verizon Data Breach Investigations Report  (10,8)  Most data breaches can be prevented with simple measures.

A Look at Today's Data Center Availability  (10,7)  The Veeam report looks at the state of today's data centers to meet their RTO and RPO SLAs.

Aberdeen's 2008 Business Continuity Survey  (3,4)  A look at 150 small to large companies and their BC/DR plans and processes.

Archive Storage - Disk or Tape?  (5,11)  Disk provides fast recovery from backups, and tape provides economical long-term archiving.

Beyond Redundancy  (7,5)  How geographic redundancy can improve service availability and reliability of computer-based systems.

Big Switch: Rewiring the World from Edison to Google  (6,9)  The cloud compute utility is following in the tracks of the electric utility.

Blueprints for High Availability: Designing Resilient Distributed Systems  (2,5)  All you ever wanted to know about clusters.

Breaking the Availability Barrier  (3,5)   Everything you ever wanted to know about active/active systems - theory, implementation, and practice.

Business Continuity from A to Z  (5,12)  The online book explores the responsibilities of the stakeholders in the business continuity plan.

Business Continuity Planning: IT Examination Handbook  (1,1)  What better way to learn about BCP than from the auditor's handbook.

Business Continuity Today  (4,3)  This freely-available living eBook covers a broad range business availability topics.

Continuous Availability Systems Design Guide  (2,1)  What to do if you want to move to CPA.

Disaster Recovery as a Service  (12,9)  Gartner reviews several companies that provide DRaaS, currently a $2 billion business.

Distributed Systems: Principles and Paradigms  (3,1)  A thorough treatment of requirements for distributed system transparency.

Fire in the Computer Room , What Now?  (2,6)  Are you prepared for a total loss of your data center because of a fire or other disaster?

Flash Boys: A Wall Street Revolt  (9,5)  A group of traders sets up the IEX stock exchange to prevent predatory practices such as front-running.

Hactivism  (11,2)  An analysis of an Anonymous attack leads to some key strategies to protect a company's website from hactivist attacks.

High Availability IT Services  (10,1)  An easy to read discussion of the roles that people, processes, and products play in high availability IT systems.

High Availability Network Fundamentals  (4,4)   A practical guide to predicting network availability (especially for the mathematically challenged).

High-Performance IT Services  (11,8)  A non-mathematical discussion of how to achieve high performance in mission-critical IT systems,

HP NonStop for Dummies  (9,10)  Finally! A Dummies book for NonStop systems is here, giving a high-level look at these fault-tolerant systems.

HPE Cyber Risk Report 2016  (11,3)  The report examines the vulnerabilities that leave organizations exposed to data breaches.

Hyperconverged Infrastructure  (12,10)  HPE has released a Dummies book describing its Hyperconverged infrastructure product, Simplivity.

Internet Disruptions  (12,5) Nearly every company has had an Internet Disruption in the past year.

IT Disaster Recovery Planning for Dummies  (10,9)  A disaster recovery plan is mandatory to survive a disaster, but many companies go without one.

Megaplex: An Odyssey of Innovation  (4,12)  Tandem is 35 years old. The Standish Group looks back on 35 years of availability innovation.

Megaplex Modeling: The Future of NonStop Demand  (5,10)  Standish Group envisions critical and non-critical applications sharing the same blades.

Migrating Legacy Systems: Gateways, Interfaces, & the Incremental Approach (2,3)  Legacy systems must be decomposed to migrate to active/active.

Mission-Critical Network Planning  (4,9)  A broad review of redundancy in servers, networks, storage, data centers, and power.

Multiple Processor Systems for Real-Time Applications  (2,10) A classic treatise on distributed systems that is still pertinent two decades later.

Pandemic Response Planning  (4,10)  How will your company continue operations if the Swine Flu hits with a vengeance?

Reliability and Availability of Cloud Computing  (10,2)  The factors contributing to downtime and how to design clouds for five 9s of availability.

Roadmap to the Megaplex  (5,7)   The six steps that will modernize your vertical NonStop applications for the open world of horizontal services.

Tandem Computers Unplugged: A People's History  (7,7) Tandem from 1975 till 1997 as seen through the eyes of its employees.

Targeted - The Story of a Pathological Serial Work Place Bully  (10,6)  A workplace bully costs the job of the author at three companies.

TCP/IP Illustrated, Volume 1: The Protocols  (4,11)  The "bible" of the TCP/IP Protocol Suite, the glue that binds active/active systems.

The Business and Economics of Linux and Open Source  (1,3)  Open source demystified for the reluctant manager.

The Cost of Data Breaches  (11,1)  The Ponemon Institute finds that the average cost of a data breach in 2014 was USD $3.79 million.

The Cost of Data Center Outages  (10,12)  The Ponemon Institute finds that the average cost of a datacenter outage in 2013 was $690,000.(12,2)

The Disaster Recovery Journal  (5,2)  The resource for business continuity professionals.

The High Availability Design Spectrum - Part 1  (11,12)  Dr. Terry Critchley sets forth his first four observations on designing for high availability.

The High Availability Design Spectrum - Part 2  (12,1)  Dr. Terry Critchley sets forth his next nine observations on designing for high availability.

The High Availability Design Spectrum - Part 3  (12,2)  Dr. Terry Critchley sets forth his next six observations on designing for high availability.

The High Availability Design Spectrum - Part 4  (12,3)  Dr. Terry Critchley sets forth his final four observations on designing for high availability.

The Unified Modeling Language User Guide  (1,2) UML is now the accepted standard for fast and easy documentation of systems and procedures.

Towards Zero Downtime: High Availability  Blueprints  (2,8) A close look at installing Microsoft clusters and cluster-aware applications.

Transaction Processing: Concepts and Techniques  (2,4) The classic book on transaction processing systems, by Jim Gray and Andreas Reuter.

Unix Backup and Recovery  (2,2)  Backing up is a pain, but it is the restore that counts.

  Product Reviews

Ace Data Recovery  (9,12)  Ace recovers lost data from hard disks, RAID arrays, solid-state drives, tape, mobile devices, and cloud environments.

Attunity Integration Suite  (5,12)  Data access, data federation, and data movement combine to make data and services available across the enterprise.

Attunity Replicate  (9,8)  Attunity Replicate is an appliance-based data-replication engine that supports active/active across heterogeneous databases.

Carbonite - The Online File Copy Utility  (12,6)  Carbonite automatically copies new and modified files to its own online storage for later retrieval.

CenturyLink Targets Six Nines  (11,6)  The U.S. telco giant is aiming to offer its customers six nines of reliability in its SLAs.

Critical Date Testing - Leap Day and More  (7,5)  Many products exist to test applications for proper processing of critical dates.

EMC's SRDF Data-Replication Engine  (6,4)  Maintain a consistent asynchronous or synchronous target copy of a database with no server involvement.

Everbridge Emergency Notification  (7,9)  Preplanned mass notification to employees, customers, and suppliers is a must during an emergency.

FalconStor RecoverTrac - Automated Disaster Recovery  (7,6)  Build your own recovery cloud supporting heterogeneous environments.

Fault-Tolerant Windows and Linux from Stratus  (2,9)  ftServers provide transparent fault-tolerant operation.

Fault Tolerance with everRun from Stratus  (10,12)  Two x86 servers coupled with synchronous replication provide fault tolerance with no data loss.

FileSync and CSR Synchronize NonStop Systems: Part 1 - FileSync  (6,10)  FileSync replicates changed files or file changes between systems.

FileSync and CSR Synchronize NonStop Systems: Part 2 - CSR  (6,11)  Command Stream Replicator repeats operator actions on remote systems.

Flexible Availability Options with GoldenGate's TDM  (2,2)  Implement a variety of data-sharing topologies with TDM's data replication facilities.

GRIDSCALE - A Virtualized Distributed Database  (3,7)  Like presentation and application servers, pooled database servers for the three-tier architecture.

How Much Will Active/Active Cost Me?  (1,1)  The cost of downtime can swing your decision.

HPE Helion Private Cloud and Cloud Broker Services  (11,2)  HPE provides an OpenStack private cloud and services to implement hybrid clouds.

HP NonStop Servers Migrated to x86  (10,5)  NonStop servers now combine commodity technology with open software.

HP Serviceguard Cluster Arbitration and Fencing Mechanisms  (9,1)  Quorum systems handle partitioning of clusters in the face of network faults.

HP's NonStop Blades  (3,8)  NonStop fault-tolerant fundamentals come to HP's c-Class blades.

HP's NonStop Synchronous Gateway  (4,6)   Finally, NonStop synchronous data replication might be on its way.

HP's Reliable Transaction Router  (5,5)  Reliable transaction messaging services between Windows, Linux, OpenVMS, and HP-UX systems.

HP's ServiceGuard Clustering Facility  (2,5)  Managing HP-UX and Linux clusters.

Introduction to HP Serviceguard Clusters  (9,3)  HP's clusters protect applications from failures and service interuptions.

Master/Slave Replication with Continuent's Tungsten  (4,5)  Asynchronous replication between MySQL and Oracle.

MySQL Clusters Go Active/Active  (1,3)  Clusters of storage nodes are kept in sync by synchronous replication.

Nagios Open-Source Monitoring for HP NonStop  (8,3)  Manage your NonStop systems along with your Windows, Linux, and Unix systems with Nagios.

Neverfail for Windows Applications  (5,6)  Automated failover is provided for popular Windows applications like Exchange, SharePoint, SQL Server, IIS.

NonStop AutoSYNC - Eliminating Configuration Drift  (6,8)  Backup system configurations must be kept synchronized with their production systems.

OpenVMS Active/Active Split-Site Clusters  (3,6)  OpenVMS Clusters provide active/active operation with synchronous replication.

OpenVMS Emulation on PCs  (8,9)  vtAlpha and vtVAX emulate Alpha and VAX hardware on multicore x86 PCs with no software changes.

Oracle Data Replication  (6,9)  Data Guard, Streams, or GoldenGate - Which replication engine should be used when?

Parallel Sysplex - Fault Tolerance from IBM  (3,4) IBM's Parallel Sysplex offers offers localized active/active availability.

Pathway - HPE NonStop's Application Environment  (11,5)  Pathway provides transparent scalability and fault tolerance for NonStop applications.

Penguin Computing Offers Beowulf Clustering on Linux  (2,1)  NASA's Beowulf clustering is available on Linux with Penguin's HPC servers.

Prolexic - A DDoS Mitigation Services Provider  (8,4)  Prolexic protects companies from DDoS attacks via a network of scrubbing centers.

Protect your mission-critical applications with HP Serviceguard Solutions for Linux  (8,10)  A capability of HP's Insight Manager.

Raima's High-Availability Embedded Database  (6,12)  A microprocessor embedded database with SQL capabilities offering five 9s availability.

Redundant Load Balancing for High Availability  (8,7)  Loadbalancer.org's redundant load balancers eliminate a single point of Intranet failures.

Replicating Windows and Linux Environments with Double-Take  (4,8)  Replicate entire servers with incremental file-system updates.

Scaling MySQL with Continuent's uni/cluster  (3,11)  Synchronous replication of update queries and distribution of read queries.

SchoonerSQL Brings Five 9s to MySQL  (7,1)  Significant extensions to MySQL to improve its availability and replication performance.

Shadowbase - The Active/Active Solution  (2,3)  Shadowbase provides fast data replication as well as online copy and database resynchronization.

Shore Micro's 100-Microsecond Link Failover  (6,3)  Field-Programmable Gate Arrays protect redundant Ethernet links with 100 usec. failover.

solidDB - a Five 9s Memory-Resident Database  (3,5)   Server memory is getting so large, why not keep your database in high speed memory?

Stratus Avance Brings Availability to the Edge  (4,2)  If downtime in a branch office costs as little as $1,000 per hour, Avance can pay for itself in a year.

Stratus Continues its $50,000 Uptime Guarantee  (10,3)  Stratus has not paid a cent on its guarantee for five years.

Stratus' ftServer Flexes Its Recovery Muscle  (5,8)  Independent testing measures scalability and demonstrates no impact due to catastrophic failure.

Surviving DNS DDoS Attacks  (8,11)  The Secure64 DNS Authority server detects and blocks DDoS traffic while continuing to respond to DNS queries

TANDsoft FileSync Adds Deduplication  (9,2)  The bandwidth and time needed for file synchronization is greatly improved with data deduplication.

Testing for Y2038 and Y2028  (12,5)  Two utilities for testing for critical date/times are reviewed - Softdate and OPTA2000.

The Uptime Institute  (10,10)  The Uptime Institute provides Tier-based standards for data center topology and operational sustainability.

Time Synchronization for NonStop Servers  (02,11)  NTP products  from Bowden Systems and HP for NonStop servers.

Verisign DDoS Mitigation Services  (8,12)  Verisign's cloud mitigation service defends against even the largest DDoS attacks.

Virtual Tape - Getting Rid of a Troublesome Medium  (1,2) The backup paradigm is changing.  Goodbye, tape.

Virtual Tape for NonStop Servers with ETI-NET's EZX-BackBox  (2,6)  Virtual tape made super-fast with deduplication.

Virtual Transactions with NonStop AutoTMF  (2,4) Converting nontransactional applications to transactional applications.

Virtualized Time from TANDsoft  (4,1)  The OPTA2000 Time Simulator lets  multiple applications run on the same NonStop system with different clocks.

VMTurbo - Managing Virtualization  (10,4)  VMTurbo is a management tool that automatically reconfigures virtual environment to maintain SLAs.

VSI to Port OpenVMS to x86  (10,11) VMS Software, the support organization for OpenVMS, will port the operating system to run on x86-64 servers.

Windows Server Failover Clustering  (5,4)  Microsoft's successor to MSCS adds simplified cluster management and improved geographical dispersion.

  The Geek Corner

Calculating Availability - Redundant Systems  (1,1)  Some useful rules come out of the derivation of the availability equation.

Calculating Availability - Repair Strategies  (1,2) Your repair policy can have a significant impact on your system availability.

Calculating Availability - The Three Rs  (1,3)  Node repair, node recovery, and system restore are all required.

Calculating Availability - Hardware/Software Faults  (2,1)  Most faults don't need a repair.

Calculating Availability - Failover  (2,2)  When a system is failing over, it is often effectively down, thus reducing availability.

Calculating Availability - Failover Faults  (2,3)  Failovers can fail also.

Calculating Availability - Environmental Faults  (2,4) How to handle hurricanes, power failures, and riots when calculating availability.

Calculating Availability - Cluster Availability  (2,5)  How does the availability of a cluster compare to that of an active/active system?

Calculating Availability - Nodes, Subsystems, and Systems  (2,6)  When is a node a system, and when is it a subsystem?

Calculating Availability - Failure State Diagrams  (2,9)  Formalizing our intuitive derivations.

Calculating Availability - Heterogeneous Systems - Part 1  (3,3)  Probability 101 in preparation for analyzing systems with heterogeneous nodes.

Calculating Availability - Heterogeneous Systems - Part 2  (3,5)  The availability of redundant systems with different nodal availabilities.

Calculating Availability - Heterogeneous Systems - Part 3  (3,6)  Analyzing complex configurations of system components.

Calculating Availability - Heterogeneous Systems - Part 4  (3,8)  Demonstrating that systems with century uptimes can be configured.

Calculating RPO  (5,3)  An RPO is the probability that data loss following a node failure is less than a specified amount. How can we verify this?

Configuring to Meet a Performance SLA - Part 1  (3,12)  What size server is needed to provide a response time of 200 msec. 98% of the time?

Configuring to Meet a Performance SLA - Part 2  4,1)   Comparing the performance of single-server systems to multiserver systems.

Configuring to Meet a Performance SLA - Part 3  (4,2)  Answering the SLA specification for servers with exponential service times.

Configuring to Meet a Performance SLA - Part 4  (4,3)  Answering the SLA specification for servers with arbitrary service times.

Configuring to Meet a Performance SLA - Part 5  (4,4)  Answering the SLA specification for multiple servers in tandem.

Dr. Bill's Doctoral Thesis  (12,8)  Dr. Bill researched Linear Decision Functions, With Application to Pattern Recognition" for his doctor's thesis.

Estimating Data Collision Rates  (2,8) Can you go active/active with a tolerable level of data collisions?

Failure State Diagrams - Repair Strategies  (2,10) The real story behind sequential repair and parallel repair.

Failure State Diagrams - Recovery Following Repair  (2,12)  The formal analysis of the impact of having to recover a node after its repair.

Failure State Diagrams - Hardware/Software Faults Revisited  (3,2)  Our intuitive results were a little simplistic.

Google Will Help You Manage the 2016 Leap Second  (11,12)  You can use Google's NTP server to get the leap second as 'smeared time.'

Improving Availability via Staggered Systems  (12,2)  Optimize availability by minimizing the probability that both systems will fail simultaneously.

Is Parallel Repair Really Better Than Sequential Repair?  (3,4) A Digest reader points out that that depends upon the repair time distribution.

Modem Memories  (10,11)  Dr. Bill developed one of the first AT&T modems, the DataPhone 103, back in 1958.

Not Only the Y2038 Problem - There's a Y2028 Problem  (12,5)  The Y2028 problem was caused by a 'temporary' Y2K work-around.

Random Events Have No Memory  (9,11)  MTR and MTBF are random events characterized by the exponential and Poison probability distributions.

Reliability Diagrams  (6,7) Complex systems can be analyzed via reliability diagrams as sets of parallel (redundant) and serial components.

Repair Strategies  (9,10)  The repair strategy used by an enterprise can have a significant impact on application downtime.

SAP on VMware High Availability Analysis  (7,12)  Our availability analysis is used to predict the availability of  VMware ESXi clusters.

Simplifying Failover Analysis - Part 1  (5,10)  User's aren't down just because two nodes fail. They are also down waiting for a backup system to take over.

Simplifying Failover Analysis - Part 2  (6,6)  Extending failover analysis to complex multinode systems.

So You Want to Mine Bitcoins?  (9,4)  A lot of money can be made by generating bitcoins, but only for a few.

Software Reliability Models  (8,8)  Modeling software reliability is a complex task upon which there is not much agreement.

The Cost of RPO and RTO  (7,9)  What is the optimum architecture for minimizing the costs of downtime and lost data?

The Fallacy of Classic Availability Theory  (12,1)  MTBF and MTR are memoryless variables. Use MTTF instead.

What's That Nerd Logo?  (1,1)  Our logo, ff2, really has a meaning. Find out why it describes active/active architectures.

Why Are Active/Active Systems So Reliable?  (3,9)  Analyzing the impact of resubmitting transactions rather than bringing up a backup system.

Writing Patent Applications  (13,8)  One of my writing services is to prepare patent applications for my customers. In this article, we talk about the format for patent applications.


@availabilitydig - The August, 2013, Twitter Feed of Outages  (8,8)

@availabilitydig - The September, 2013, Twitter Feed of Outages  (8,9)

@availabilitydig - The October, 2013, Twitter Feed of Outages  (8,10)

@availabilitydig - The November, 2013, Twitter Feed of Outages  (8,11)

@availabilitydig - The December, 2013, Twitter Feed of Outages  (8,12)

@availabilitydig - The January, 2014, Twitter Feed of Outages  (9,1)

@availabilitydig - The February, 2014, Twitter Feed of Outages  (9,2)

@availabilitydig - The March, 2014, Twitter Feed of Outages  (9,3)

@availabilitydig - The April, 2014, Twitter Feed of Outages  (9,4)

@availabilitydig - The May, 2014, Twitter Feed of Outages  (9,5)

@availabilitydig - The June, 2014, Twitter Feed of Outages  (9,6)

@availabilitydig - The July, 2014, Twitter Feed of Outages  (9,7)

@availabilitydig - The August, 2014, Twitter Feed of Outages  (9,8)  (9,8)

@availabilitydig - The September, 2014, Twitter Feed of Outages  (9,9)

@availabilitydig - The October, 2014, Twitter Feed of Outages  (9,10)

@availabilitydig - The November, 2014, Twitter Feed of Outages  (9,11)

@availabilitydig - The December, 2014, Twitter Feed of Outages  (9,12)

@availabilitydig - The January, 2015, Twitter Feed of Outages  (10,1)

@availabilitydig - The February, 2015, Twitter Feed of Outages  (10,2)

@availabilitydig - The March, 2015, Twitter Feed of Outages  (10,3)

@availabilitydig - The April, 2015, Twitter Feed of Outages  (10,4)

@availabilitydig - The May, 2015, Twitter Feed of Outages  (10,5)

@availabilitydig - The June, 2015, Twitter Feed of Outages  (10,6)

@availabilitydig - The July, 2015, Twitter Feed of Outages  (10,7)

@availabilitydig - The August, 2015, Twitter Feed of Outages  (10,8)

@availabilitydig - The September, 2015, Twitter Feed of Outages  (10,9)

@availabilitydig - The October, 2015, Twitter Feed of Outages  (10,10)

@availabilitydig - The November, 2015, Twitter Feed of Outages  (10,11)

@availabilitydig - The December, 2015, Twitter Feed of Outages  (10,12)

@availabilitydig - The January, 2016, Twitter Feed of Outages  (11,1)

@availabilitydig - The February, 2016, Twitter Feed of Outages  (11,2)

@availabilitydig - The March, 2016, Twitter Feed of Outages  (11,3)

@availabilitydig - The April, 2016, Twitter Feed of Outages  (11,4)

@availabilitydig - The May, 2016, Twitter Feed of Outages  (11,5)

@availabilitydig - The June, 2016, Twitter Feed of Outages  (11,6)

@availabilitydig - The July, 2016, Twitter Feed of Outages  (11,7)

@availabilitydig - The August, 2016, Twitter Feed of Outages  (11,8)

@availabilitydig - The September, 2016, Twitter Feed of Outages  (11,9)

@availabilitydig - The October, 2016, Twitter Feed of Outages  (11,10)

@availabilitydig - The November, 2016, Twitter Feed of Outages  (11,11)

@availabilitydig - The December, 2016, Twitter Feed of Outages  (11,12)

@availabilitydig - The January, 2017, Twitter Feed of Outages  (12,01)

@availabilitydig - The February, 2017 Twitter Feed of Outages  (12,02)

@availabilitydig - The March, 2017 Twitter Feed of Outages  (12,03)

@availabilitydig - The April, 2017 Twitter Feed of Outages  (12,04)

@availabilitydig - The May, 2017 Twitter Feed of Outages  (12,05)

@availabilitydig - The June, 2017 Twitter Feed of Outages  (12,06)

@availabilitydig - The July, 2017 Twitter Feed of Outages  (12,07)

@availabilitydig - The August, 2017 Twitter Feed of Outages  (12,08)

@availabilitydig - The September, 2017 Twitter Feed of Outages  (12,09)

@availabilitydig - The October, 2017 Twitter Feed of Outages  (12,10)

@availabilitydig - The November, 2017 Twitter Feed of Outages  (12,11)

@availabilitydig - The December, 2017 Twitter Feed of Outages  (12,12)

@availabilitydig - The January, 2018 Twitter Feed of Outages  (13,01)

@availabilitydig – The February, 2018 Twitter Feed of Outages  (13,01)


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