Matt, what kind of disks do you have in you NetApp?
15k SAS. We only have the base unit (no extra shelves) though so there's only 20 disks, and the active/active setup means our main aggregate only has one RAID-DP group with 16 disks in it to.
I saw this at a previous job where we have a FAS3020 with SATA, though it was limited to VMs that were doing a decent amount of disk writes during the snapshot period.
We found that while the snapshot was been merged in a second delta file would be create to handle current writes and during this time we saw no issues, but when this second delta file was been merged in we'd see the VM enter a paused state from internal or external monitoring. Moving these VMs to FC disk resolved the problem as the snapshots were smaller - faster VCB backup, the resulting delta file created during merge was smaller and the merge of the delta did not cause a noticeable interruption to the OS or application.
Did you get the same/similar errors in your vmkernel log as the one I posted above?
iI don't think the problem is the same as the one you described though - our "normal" disk workload is very low (maybe 1-2 MB/s read/write and <10% disk utilisation from sysstat on the filer), and the VM whose snapshot-commit lead to me making this post had almost no disk I/O happening - especially writes -when I comitted the snapshot.
Really do appreciate the input though, thanks. I opened a SR with VMware yesterday about the issue, not response yet though - will post back here with the outcome for the benefit of others.
Cheers,
Matt
