A couple of weeks ago a customer reported problems with a DPM 2016 server with Modern Backup Storage (MBS). Modern Backup Storage is a new approach of DPM to get a more efficient and flexible storage pool without the known limitations of the LDM database. With MBS you use storage spaces on the DPM server to add the disks to a large pool. Then on top of the storage space you create a volume or several with shares that the DPM server can use as storage instead of adding unallocated disks that DPM manages.
An explanation on MBS is not part of the scope of this blog but the problem that we had with it is related to Storage Spaces and more specific to ReFS volumes. ReFS is the new file system Microsoft has been cooking on for the last 6+ years. It has many improvements and several of them are used to make sure data corruption does not occur and if it occurs it repairs it automatically or takes actions to prevent it.
So why seems the volume on this DPM server offline, inaccessible and corrupt in a RAW file format?
In this setup