This article discusses potential issues involving the Datto device encountered when expanding storage on protected machines.
Over time, storage requirements on protected production servers can change. Often, the amount of storage needed becomes larger than than what is currently allocated, and the disk may need expansion. Since doing this can affect your backups, There are a few precautions to take.
Make sure there is enough free space available on the Datto device. This is essential. Otherwise, the disk array can fill and make all other backups fail due to lack of space. Forcing a differential merge will also fail since all sectors are different on the block level.
New GUID issues for virtual and physical protected machines
Expanding storage on VMs can mean creating a larger thick provisioned disk, which is seen as a brand-new disk. The same can be true for physical servers; the new larger disk has the same data, but it is seen as a brand new GUID. On the Datto, a new full backup will be necessary specifically for this disk.
Alternatives to disk expansion
If you need more on the Datto device to accommodate the larger disk, then you may need to speak with your sales representative about the current device size, and possible sizing alternatives. You may also be able to delete some local points to gain back additional space.