Reduce your taxes part 4 – a SAN solution

In the first blog of this series I discussed how some organizations are over-provisioning their server resources in order to balance the competing demands of performance and data protection SLAs. Parts 2 and 3 showed examples of actual SQL Server database configurations being tested to measure the impact of backups and snapshots while maintaining application performance.

Those tests showed two examples of an approximate 40% tax rate for data protection, meaning that 40% of the server processing headroom was sitting idle so that performance SLAs could be met during data protection operations.

How to reduce your taxes – So how can you reduce those taxes? This is where storage comes in to the picture. The reason that meeting service levels requires over-provisioning of your database servers in these scenarios is that server resources are being used for tasks that are best managed by a SAN. SAN-based snapshots have several advantages:

  • They are quick to create – taking under 10 seconds instead of the 10 minutes it takes to create native SQL server snapshots for the same workload use-case.
  • They have a very minor performance impact that is of no consequence to server provisioning.
  • Snapshots can be used as the source for an off-host backup, eliminating backup tax.

Here is an example of actual testing of the performance impact of SAN-based snapshots for the same SQL Server transactional database load tested in parts 2 and 3 of this series.

As you can see, CPU utilization and transactional performance are minimally impacted by the SAN-based snapshot operations. The “Smart Copy” terminology refers to the fact that these are application-consistent snapshots which have been created by momentarily quiesceing the database and flushing buffers so that a completely valid recovery point for the database is created. This is done with Microsoft VSS, and took between 4 and 8 seconds for the configuration tested.

Conclusion: By using the data protection capabilities of your SAN, you can ensure more efficient use of your IT resources and reduce your taxes to achieve IT Efficiency.

For more information on the testing that was done please refer to:

Now it is time to hear from you, what is your preffered “Tax” reduction strategy? Are you using SAN data protection?


About Bob Ganley

Enterprise Information Technology Executive, Family Man, Athlete @ganleybob on twitter
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