drunkNerd

I just read a great article from Scott Lowe on optimizing NFS storage for use with VMware. Most of the recommendations are found in Celerra best practices docs but its also nice when someone compiles them all up into one area.

• As has been stated on multiple occasions and by multiple people, be sure that virtual machine disk/application partitions have been properly aligned. We recommend a 1MB boundary. Note that Windows Server 2008 aligns at a 1MB boundary automatically.
• Use a block size of 8KB unless other recommended or required by the application vendor. Note that the default NTFS block size is 4KB.
• Turn on the uncached write mechanism for NFS file systems used as VMware datastores. This can have a significant performance improvement for VMDKs on NFS but isn’t the default setting. From the Control Station, you can use this command to turn on the uncached write mechanism:
  server_mount <data mover name> -option <options>,uncached <file system name> <mount point>
  Be sure to review pages 99 through 101 of the VMware on Celerra best practices document for more information on the uncached write mechanism and any considerations for its use.
• Change the VMware ESX settings NFS.SendBufferSize andNFS.ReadBufferSize to a value that is a multiple of 32. The recommended value is 64. See page 73 of the best practices document for more details.
• If you’ve adjusted the NFS.MaxVolumes parameter in order to have access to more than 8 NFS datastores, you should also adjust NFS.TcpIpHeapSizeand NFS.TcpIpHeapMax parameters. The increase should be proportional; if you increase the maximum volumes to 32 (a common configuration), then you should increase the other parameters by a factor of 4 as well. Page 73 of the best practices document covers this. This VMware KB article andthis VMware KB article also have more information.
• Although not directly related to performance, best practices call for settingNFS.HeartbeatFrequency (or NFS.HeartbeatDelta in VMware vSphere) to 12, NFS.HeartbeatTimeout to 5, and NFS.HeartbeatMaxFailures to 10.
• Ensure that the LUNs backing the NFS file systems are allocated to the clar_r5_performance pool. This configuration will balance the load across the SPs, LUNs, etc., and help improve performance.