This may be a dumb question, but I can't seem to find any definitive information after having done many, many searches. Short question is - can Windows Server Backup spread a single backup job across multiple disks if they are not in a storage pool or some other RAID/JBOD structure?
Background:
I'm running Server 2012 Essentials with all Windows Updates installed. I have been backing up approx 2.8TB of data (Bare Metal Recovery, C:, S: (shared folders), and system reserved) for the past year+ onto a storage pool made up of two-2TB external USB drives. Backup is slow (takes approx 1.5 days to complete), but generally works. Not surprisingly I was constantly getting capacity low messages so I decided to increase my backup storage pool by adding a 3TB drive and another spare 750GB drive for a total of 7.75TB. Instead of having four separate external USB enclosures, I bot a 4-bay enclosure - Startech.com model #S3540BU33E to simplify this (or so I thought!).
The first problem I had was adding the two new drives to the existing storage pool. I think that is because the Startech uses a JMicron USB controller that reports identical uniqueid's for all drives so only one shows up in the GUI interface for creating storage pools. After doing research on this, I set up a new storage pool and virtual disk using all four drives via Powershell and thought I was good. However, when the backup ran, it failed after filling the first drive, saying there was no remaining capacity. In reality there were three remaining empty drives and there storage pool reported almost 5TB of avail capacity. I assumed this was due to the identical uniqueid issue so I decided to try a different tactic.
Instead of using a storage pool that combines all four disks into one virtual disk, I just added each of them to Windows Server Backup as individual drives thinking it would manage them collectively. I.e., when a drive filled up during a particular backup, it would just start using the next drive and so on. Apparently this was a foolish assumption because the backup failed again as soon as the first disk filled up.
So now I don't know if this is still an issue with the identical uniqueid's or if Server Backup actually can't spread a single backup across multiple individual drives that aren't in a pool or other virtual disk implementation. Hence, my original question.
My guess is that it does *not* spread them across individual disks, but I just wanted to get confirmation.
Thanks
