Delete snapshots or files didn't free up space

[FelixZhou]

We deleted snapshots and files but didn't  free up any space.

It has been bothered me for a while so far no clue what happened. Can someone give me some ideas?

We are on OnTap 9.10 with AFF servers.

Example one:

We have a CIFS share around 12TB, my application team moved 4TB data (hospital images) to another share and expected to free up some space.

After we cleaned up all snapshots (seeing the deleted data), we still couldn't see free space from the share or volume.  our aggregate only gets 1:1.7 overall deduplication and compression saving, deleted 4TB not even free up 100GB space. i couldn't explain.

Example two:

We have some datastores (sized as 8TB)on VMware alerts lack of space. After we checked around, we found we have some big SnapCenter snapshots on these volumes, we deleted all big snapshots around 3TB in size, then when check the snapshot and volume usage with "df -h" we didn't see any space freed up. After rescan storage on VMWare, these datastores still alerting of space shortage.

Can someone please explain to me what is happening?

thanks in advance !

[paul_stejskal]

Is the space clearing up gradually? If you check node shell "wafl scan status" (advanced/diag level privilege), do you see a container block reclamation scan on that volume?

[TMACMD · Accepted solution]

Deleting all snapshots should free up space. It can take up to an hour or more for the scanners to clear everything up. 

if you are only deleting some snapshots, then it’s entirely possible you may not free up as much space as you want. The changed blocks may be in snapshots before or after what was deleted