I have seen this on a few installations with Windows Server SBS 2011 if the backup is configured through the SBS console backup wizard. Which is also the correct way to setup backup in SBS 2011. If you not have virtualized it, then you would of course use Veeam, right..?
As you can see from the screenshot the disc is just using half of the drive. If I run 10 backup it will still just hold 73 restore points back in time. The problems is realted to the shadow copies. Type this to see if you have the same problem:
To check if you have the same problem I have seen type this command
vssadmin list shadowstorage
and see if you can see the UNBOUNDED. If you got that on your usb-drive, thats your problem.
To release this UNBOUNDED space, do the following:
- associate a drive letter to your usb-drive
- type the following in a cmd.exe where x: is the drive letter you assigned your backup drive
vssadmin resize shadowstorage /for=x: /on=x: /maxsize=1.8TB (or the size of your drive -10%)
- Remove the drive letter from the usb-drive
You should now see that you have released the space if you tyoe: vssadmin list shadowstorage