I setup 4 VDR 2.0 appliances in our ESX 4.0 environment. 4 is required as we have roughly 7 TB of backups, and VDR maxes at 2 1TB drives. The drives are on a datastore residing on an iSCSI device. There are 3 ESX hosts on an iSCSI LAN with the storage device.
To see how well multiple VDR performed side by side, I set 1 to do a backup job of a larger VM, 500gb. A set another to do 3 virtual machines, each 50-100gb in size. Shortly after starting, our mail server which was not being backed up, starting showing logon errors for various users. I stopped the backups and everything returned to normal.
My thought is that VDR was causing heavy disk I/O and slowed down the mail server. We had recently used VCB backups and never ran into an issue like this. Thoughts?
