Is it possible to change the drive that Microsoft DPM backs up to? A while ago our sysops guys created a 15 minute transaction log backup schedule using Microsoft DPM.  We often have an issue where there won't be enough space on the Log drive to perform a backup because DPM creates its backup on the same drive that the logs live on. Eventually, because DPM can't back up the logs, they get larger and larger and the problem gets worse and worse until I run a manual backup of the bloated logs through SQL Server (and then, sadly, I have to run Shrinkfile on the logs that bloated). 

I can't find any setting or option in DPM that allows me to write the backups to a different drive with more space instead of the drive that the logs sit on.  Does anyone know if it's possible to do this and how?
DPM and Windows Server Backup make a determination when the agent is installed as to which drive it would use for System State Backups. 

This by default is the drive with the most available free space. That information gets saved into the PSDataSourceConfig.XML file.

WARNING:
If the server you are protecting is a member of a cluster, it is possible that a cluster drive will be selected in this process. If that drive ownership has been switched to another node, then next time system state for the node is done, the drive is no longer available and the backup will fail. In this situation, you will need to modify the PSDataSourceConfig.XML to point it to a local drive.


On the server you are backing up, navigate to C:\Program Files\Microsoft Data Protection Manager\DPM\Datasources.
There you will find a file named PSDataSourceConfig.XML. Right click that file and choose to edit.
Find the section for  which is followed by a drive letter and WindowsImageBackup. This will be the current location WSB will put the files.
Modify the file to reflect the drive letter you want WSB to use.