I've been testing VDR 1.0.1 for a while now, it works fine for me so far, but there is one possible serious issue I'm pondering about now:
Old restore points are being deleted according to my configured retention policy:
8/6/2009 1:16:37 PM: Executing Reclaiming
8/6/2009 1:16:37 PM: Reclaiming Destination /SCSI-0:1/...
8/6/2009 1:16:54 PM: Deleted restore point 7/30/2009 10:09:35 AM for virtual machine MY_VM1
8/6/2009 1:19:59 PM: Task completed successfully
8/6/2009 1:19:59 PM: Duration: 00:03:22
Seems like everything goes according to plan here, no issue.
However the actual disk space used by VDR never decreases on my VDR box, even though it delted a few dozen restore points already.
Thinking about the way VDR backups work, this actually seems quite natural and logical to me:
VDR creates an initial full backup on the first backup, and then only incremental ones for all subsequent backups. So if you want to restore from a restore point from yesterday, you need to have the data of the initial + all other incremental backups ever made for that VM, regardless of whether you still have the actual restore points of all those incremental backups. That way (by that design), it is impossible for VDR to ever decrease the used disk space, unless you delete the most recent restore point or the whole VM from VDR of course.
This means it should make no difference to the disk space whether your retention policy keeps one or one hundred restore points. If you restore the most recent restore point from any of those policies, VDR still has to process all the data of all previous backups, applying changes one after another as those backups happened. "Merging" such a block-level disk backup seems impossible to me, or does it really do something like that?
Someone please clarify if this theory is applicable, or if am I horribly mistaken here?! if I am in fact mistaken, why is my used disk space not only rising steadily?