jaredplaisted wrote:Just a quick question how many VM's per CSV do you have?
Sharing something we encountered about 2 years ago when we first started using Hyper-V 2012 R2 which maybe relevant.
We used to have similar issues to what you describe, back then we had large CSV's (3PAR) with approximately 20-30 vms per CSV and experienced latency and VM freezing temporarily when ever backups ran, even if backing up a single VM every other VM in the same CSV would get hit bythe issue, regardless of throttling limits, software or hardware vss provider the issue persisted. This freezing/latency would only occur during the first part of the Backup job while the snapshot is being created, after the snapshot was created and the backup began reading/transferring data performance would return to normal.
Since we re-architected our CSV's and reduced the number of VM's per CSV down to 5-10 we no longer encounter the issue, we can run mutliple concurrent backups across multiple CSV's and don't experience any latency or issues now.
We do indeed have a large number of VM's per CSV (20-30). Reducing the number of VM's and increasing the number of CSV's could be a good idea.