The data store status changes to “Restore only (Degraded State)”. The status of the data store will change to 'Restore only (degraded state)' but it will still be in a “running” state.
This issue happens if the hash role has reached its maximum allocated memory.
The jobs will continue to run however any new unique data will not insert hashes into hash database, and the deduplication percentage may reduce or might not happen.
You should still be able to perform restores.
We happened to check status of Data Store under Recovery Point Servers and found it is not in active state.
The solution to this is to make sure that the data store gets enough memory to load the contents of the hash database. For this check the location of the hash destination on the file system and increase the “Hash Memory Allocation” to more than the current size of the “Hash Destination”
Select Recovery Point Server and click on Modify .
Increase Hash Memory Allocation to more than the current size of the “Hash Destination”
Now able to start Data Store successfully.