There has been a lot of discussion(check Scott’s take on this) around this advanced NFS setting called “NFS.LockDisable”. In short, you can disable the locking mechanism on NFS volumes with this setting.
In the past NetApp had a best practices document which stated that it should be disabled by setting it to “1”. But, as some noticed this can and probably will result in corrupt file-systems. So this “best practice” mysteriously disappeared from the NetApp VI3 Best Practices guide and a KB Article with the VMware best practice on this setting popped up.
So if you did set “NFS.LockDisable” to 1 please change it back to “0”.
It might be beneficial to also implement the “prefvmx.ConsolidateDeleteNFSLocks” that Scott discussed along with patch ESX350-200808401-BG. This setting is to avoid long delays when deleting ESX snapshots. This can take up to 30 seconds, which is quite long compared to iSCSI or FC. So you should only implement this fix if you run NFS and do VMware snapshots at them same time and are experiencing these dalays.
I do recommend that everyone with an NFS filer takes a look at the NetApp best practices document because it does contain valuable information, but before you apply it besure that it doesn’t conflict with a VMware best practice!
Duncan, can you shed any light on the prefvmx.ConsolidateDeleteNFSLocks setting? Is this something that should be implemented ONLY by those who had previously disabled NFS locking, or is this a setting that ALL users should implement, even if NFS locking had never been disabled?
Well, as far as I know this setting isn’t a best practice yet. So it’s definitely not something ALL users should implement. But those who are experiencing delays during snapshot removals should implement it. I changed my article a bit to make it clear why one should change this setting
Correct, it is not a best practice (yet). But, if you are using NFS datastores and are using VMware snapshots (or users that are using SnapManager for VI, because SMVI utilizes VMware snapshots) it is required to implement prefvmx.ConsolidateDeleteNFSLocks or else your Virtual Machines will freeze for around 20-30 seconds when removing the VMware Snapshot.
Hi Duncan.
(I know this blog post relates to ESX v3.x but if anyone finds this (as I did) through Google I hope they read this comment.)
During a search for the settings for vSphere 4 implementation I found this official document from VMware with their statement on NFS.
Page 9 of http://vmware.com/files/pdf/VMware_NFS_BestPractices_WP_EN.pdf states the position on the NFS Locking and settings for vSphere 4.
NetApp have updated their documentation too (July 2010)
http://media.netapp.com/documents/tr-3749.pdf
Cheers,
Darren.
(@dawoo)