SQL 2008 SP2 and ESXi 4.1

[DavidRiberdy]

Our company is weighing the choice of migrating our SQL servers from physical to virtual and our DBAs are concerned that the virtual machines will not be as robust as their physical counterparts.  The servers are Windows 2003 SP2 Enterprise with SQL Server 2008 SP2 Enterprise.  All the disks will be RDMs as outside of the boot disk, we will be swinging over all the existing drives.  They will be moving from dual E5450 processors with 32GB of RAM and the new ESXi servers are dual X5660 processors with 96GB of RAM so we can allocate the full 32GB if needed.  Outside of using VMware Paravirtual SCSI Controller Types and the VMXNET3 NIC driver, who can we assure that they will not notice any performance difference between Physical and Virtual?

[kjb007]

How busy are your servers now running on physical?  In terms of  CPU/Memory, you seem to be able to match like for like.  ESX itself can  drive a lot of IO, the trick, is to make srue your storage underneath  can handle it.  Since you'll be moving the existing disks over, the  performance should be the same, as you're using the same number of  spindles.

You may want to check through the doc below in case you haven't already.

http://www.vmware.com/files/pdf/perf_vsphere_sql_scalability.pdf

[DavidRiberdy]

Memory always seems maxed out since SQL is using everything that it can.  The CPUs really don't ever seem to get over 25% utilized.  The disk I/O is running well within the IOPS allowed per spindle.

[kjb007]

Then you've pretty much covered the metrics used to determine virtualization candidacy.  You have CPU cycles, memory, and storage will be the same.  If networking falls within limits, then there should be no doubts.

If you were running high on the CPU cycles, which if you're running a high vm to host ratio, is the most oversubscribed resource, typically, then you may think twice about virtualizing.  But, you are not in that scenario.

Nothing will ease doubts more simply than doing the P2V, and showing the result.

-KjB