Thursday, November 18, 2010

Two Things from SQL Pass

I attended SQL Pass in Seattle last week and found the attendees to be a bunch of knowledgeable SQL Server DBAs.  While this may not be a surprising thing for me to say about THE conference for SQL Server, I did learn two things from talking and interacting with everybody I met.

One thing that didn't surprise me was that most SQL Server DBAs were already on board with running, at least some, production level SQL Server databases on VMware vSphere VMs.  What a lot of them wanted was a better understanding of the vSphere virtualized infrastructure that they were running on to be able to have more productive conversations with their vSphere and SAN administrators.  This leads to two things: special VM performance counters in the guest and Storage I/O Control (SIOC).

When VMtools is installed in a Windows VM it installs several things including a set of performance counters that are specific to that VMs performance.  These counters are populated with information from the ESX level for VM processor and VM memory usage.  These counters give an accurate look at how these resources are being used or consumed by the VM and not affected by the VM being virtualized.  They are under VM Processor and VM Memory in windows performance monitor (aka perfmon).  DBAs can use this performance information when talking to their vSphere admins to have a more productive conversation.

SIOC is a new feature with vSphere 4.1 that allows for VMs to be assigned different levels of priority to a given LUN.  It is coordinated across all of the vSphere hosts so that the priority is enforced even if the VMs are on different physical hosts.  For DBAs this means that if you have some SQL Server VMs that really need to be guaranteed higher levels of storage performance, you can use SIOC to ensure that a poorly written query on an unimportant DB doesn't take all of your I/O performance.


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