ESX VM swap on NFS: If it crashes, try something else
I’ve written about running VMware ESX with VM swap on an NFS datastore previously – specifically whether or not it was supported/recommended:
After writing the second post, I thought the issue was pretty much resolved: From multiple sources, the consensus seemed to be that running ESX with VM swap on NFS would be fine. Imagine my surprise (and disappointment) at seeing the following VMware KB article 1008091, updated yesterday: An ESX virtual machine on NFS fails with swap errors. Further details are in the article itself, but VMware’s KB site is throwing intermittent errors for me at the moment, so I’ll provide the money quote:
The reliability of the virtual machine can be improved by relocating the swap file location to a non-NFS datastore. Either SAN or local storage datastores improve virtual machine stability.
Unfortunately we’ve been hit by the issue mentioned in the linked KB articles. Two of our VMs on NFS just stopped running with the swap errors in the logs. It’s a shame as we’ve been running production VMs on NFS without issue for around a year now. Now I’m more than a little concerned about the other 100+ VMs still on NFS..
We hadn’t finished moving our NFS VMs off of iSCSI swap when the latest guidelines came out. If it weren’t for all the other advantages of NFS – especially allowing us to utilize expensive storage more effectively – we’d be done with NFS for VMware at this point.
Oddly enough, I can’t get to the KB article right now, although I presume it’s just a KB SNAFU.
Did you get an fix on this? We are seeing this issue now and VMware support as usual is pretty hard to get a straight answer from.
We’ve stuck with the status quo, since we haven’t seen the problem (yet), and moving swap would require downtime. Out of curiosity, what are you using for your NFS server? (We’re running against a NetApp FAS3040 with ONTAP 7.2.5.)
There appears to be some internal debate over this. The KB has been pulled from public access.