So... After working with Unitrends Support in troubleshooting a slow Hyper-V Incremental backup of one of our servers, I was informed that the backups are slow because Microsoft doesn't provide a change block detection mechanism for Unitrends to leverage (unlike VMware). Accordingly, each incremental backup takes more time because Unitrends has to figure out which blocks have changed by doing a "block by block" comparison (whether this happens at the Hyper-V host or at the Unitrends appliance, I'm not sure).
I was then directed to change my backup scheme and use the Unitrends agent at the file level, which just doesn't sit right with me, since Hyper-V level backup is one of the features that sold us on Unitrends to begin with (as well as Windows Instant Recovery, but don't get me started on that...).
This is extremely frustrating to me, and it just felt like I was being offered excuses with no proposed solution. Even if it isn't a "hot" feature request, I would imagine Unitrends should be developing this to at least offer feature parity with Veeam or System Center Data Protection Manager (DPM):
Veeam Help Center - Changed Block Tracking - http://helpcenter.veeam.com/backup/70/hyperv/index.html?changed_block_tracking.html
Microsoft System Center - Protecting Hyper-V Virtual Machines - http://technet.microsoft.com/en-us/library/hh757970.aspx
Hyper-V Protection with Data Protection Manager 2012 SP1 (see Express Full Backup section) - http://www.hyper-v.nu/archives/hvredevoort/2012/12/hyper-v-protection-with-data-protection-manager-2012-sp1/
Is this support engineer correct? Does Unitrends really have no plan to develop some mechanism for change block detection/tracking with Hyper-V level Incremental Forever backups??
As mentioned earlier, I'm a bit frustrated and feeling left out in the cold. We have a small DPM deployment in place currently, and I really don't want to have to switch all our Hyper-V backups to it. If we are forced to go that route, I don't really see where Unitrends fits in our environment as a whole.