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The digest of current topics on Continuous Processing Architectures. More than Business Continuity Planning.

BCP tells you how to recover from the effects of downtime.

CPA tells you how to avoid the effects of downtime.

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In this issue:

 

   Never Again

      Sidekick: Your Data is in 'Danger'

   Best Practices

      Chillerless Data Centers

   Availability Topics

      Is the Cost of Active/Active Worth It?

   Recommended Reading

      TCP/IP Illustrated: The Protocols

 

Complete articles may be found at http://www.availabilitydigest.com/articles

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Backups Fail, Too

 

Several years ago, I had to reformat my hard disk. I backed up my data on a memory stick and launched the reformat utility. After chugging along for a while, the utility notified me that it had finished except for one two-gigabyte partition. Did I want to reformat that also? “Of course,” I said, and then watched my entire backup disappear as my memory stick, which I had inadvertently left plugged in, was wiped out.

 

Backups fail. This lesson was learned the hard way when one million Sidekick users around the world lost all of their contacts, calendars, and photos stored by their smart-phone service marketed by T-Mobile and operated by Microsoft. An upgrade gone wrong corrupted the primary database, which replicated the corruption to the backup database.

 

In talking to attendees at my online and onsite seminars, I point out that the press is rife with stories about data lost in the cloud. You must ensure that you have an independent backup of critical data. Unfortunately, Sidekick, unlike the iPhone, does not provide a means for you to back up its cloud-stored data on your local PC. Don’t put all your faith in a cloud – it can evaporate on a sunny day.

 

Dr. Bill Highleyman, Managing Editor

 


 

  Never Again   

 

Sidekick – Your Data is in ‘Danger’

 

Sidekick is a popular smart phone provided by Microsoft and marketed by T-Mobile. In addition to being a mobile phone, it provides web browsing, instant messaging, games, multimedia, social networking, web e-mail, personal information management, and downloadable software applications.

 

On Thursday, October 1, 2009, one million Sidekick subscribers around the world lost all data functionality. Though the Sidekicks still functioned as mobile phones, all access to address books, calendars, photos, and other data was gone.

 

Shortly thereafter, users started reporting in a variety of blogs and on Twitter that their Sidekicks were wiped of all personal information. The worst possible outcome was confirmed on Saturday, October 10th, when T-Mobile and Microsoft announced that all data stored for Sidekick subscribers was likely lost.

 

Gone were contact lists, photos, calendars, and to-do lists. After initially announcing that all data had been lost, Microsoft then held out hope that some of it could be recovered. One month later, the jury is still out on how successful Microsoft will be.

 

How could this have happened? Especially to Microsoft?

 

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Best Practices

 

Chillerless Data Centers

 

Data centers are energy gobblers! The energy consumption of the world’s data centers doubled from 2000 to 2005, growing from 0.5% to 1.0% of the total electrical energy generated worldwide. Today, in 2009, these data centers consume 1.5% of worldwide electrical energy; and this number is rapidly rising.

 

Equipment cooling is by far the largest consumer of electrical power next to the IT equipment itself. The most common cooling technique is to use water chillers to cool hot air flowing from the equipment bays. This cold air is then recirculated back through the bays to keep the equipment cool.

 

Both Google and Yahoo! are taking advantage of “free cooling” – the use of cool outside air – to eliminate chillers. They are locating new data centers in areas of the world where outside temperatures are naturally low so that they can cool their equipment by natural air flow. We may see major enterprises like Google and Yahoo! adopting a “follow the moon” strategy in which workloads are shifted seamlessly between data centers to take advantage of better cooling during overnight hours.

 

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Availability Topics

 

Is the Cost of Converting to Active/Active Worth It?

 

Active/active systems can bring continuous availability to applications that simply cannot be down. But converting your current active/backup system to active/active comes with a cost. Hardware may have to be upgraded, data-replication engines licensed, and applications modified.

 

These costs are offset by the virtual elimination of both unplanned and planned downtime. But is the cost of conversion worth it? That all depends upon how much your current downtime is costing you.

 

Determining whether or not to move to an active/active configuration requires some important input – what will the move cost you initially and in ongoing operational expenses, and how much does downtime cost you.

 

Once you have these figures, the determination is quite straightforward. Knowing your initial and ongoing costs and your estimated savings, you can determine your ROI and can then make the determination as to whether a move to active/active is right for your company.

 

In this article, we take a look at the costs of moving to active/active. We give two examples of determining whether these costs are justified based on the downtime savings afforded by an active/active architecture.

 

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Recommended Reading

 

TCP/IP Illustrated, Volume 1: The Protocols

 

The TCP/IP Protocol Suite is the foundation for the replication networks and the user networks that bind the nodes of an active/active system together.

 

W. Richard Stevens has written what many consider to be the “bible” of TCP/IP. In his very readable and extensive book (30 chapters and over 500 pages) entitled TCP/IP Illustrated, Volume 1: The Protocols, he takes the reader through the TCP/IP protocols from header formats to network management. He explores in detail the four layers of the TCP/IP Protocol Suite – the link, network, transport, and application layers.

 

Throughout the book, Stevens illustrates the finer points of the protocols with examples captured from a real-life TCP/IP subnet. This subnet comprised a pair of bridged Ethernet LANs connecting several servers running different operating systems. His traces of message activity for various scenarios bring the protocols to life.

 

With its exercises and solutions and its extensive bibliography, TCP/IP Illustrated is indeed a valuable reference for the serious networking practitioner or student.

 

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Managing Editor - Dr. Bill Highleyman editor@availabilitydigest.com.

© 2009 Sombers Associates, Inc., and W. H. Highleyman