As jobs written to SmartDisk auto-expire or are manually removed from Media Management, how much space should be recovered on the volume? And on the available NVSD licensing?
When opening up the NV GUI's Device Management window and clicking on your SmartDisk instance, choosing "Status" will show the information relevant for this KB article on that window's "Storage" tab.
On the Storage tab, the "Data Protected" number that you see indicates the amount of *pre-deduplicated* data that is written to SmartDisk. Once the SmartDisk deduplication process has run and all backups marked for deduplication have been processed, the "Disk used by deduplicated data" value indicates how much physical disk space is being used by the NVSD "Store" area. Lastly, you will see the "Data in staging" value, which consists of 1.) all backups *not* marked for deduplication and 2.) any backups marked for deduplication that are yet to be deduplicated.
At the time when backups written to SmartDisk reach their expiration dates, they will automatically be removed from SmartDisk and all affected values on the SmartDisk Status' "Storage" tab will very quickly update to their refreshed values as the disk space is freed up.
Also, if you open Media Management and right-click on one of the Backup SaveSets written to SmartDisk and manually choose to "Remove" that SaveSet, you will see the same behavior described directly above.
The amount of actual free disk space that is recovered as manually or automatically-expired savesets are processed will vary on how much deduplication was possible when dedupe was run on that data.
For instance, if a 100 GB backup to NVSD had almost *no duplicate chunks* of data that could be removed, when that SaveSet is removed from SmartDisk, you could expect around 100 GB of disk space to be freed up on the volume. However, if nearly all of that 100 GB of data contained in that SaveSet *are* duplicates of chunks already written to SmartDisk, you would see very little actual disk space freed up as that SaveSet expires.
What you would also see in either of the two scenarios above would be that the amount of "Data protected" drop by the 100 GB from that example. In other words, you would once again have 100 GB in additional licensed SmartDisk capacity available again for new backups, which you can compare to the "License" value at the bottom of the SmartDisk Status' "Storage" tab for your total vs. used NVSD licensing capacity.
