The used space in my pool is shrinking, but I don't know why.

[What_Is_Computer]

So my googling skills aren't good enough to find an answer it seems. I have noticed my used capacity on my pool keeps shrinking. From the 1st to the 9th my Windows reported used space went from 875GB down to 756GB. I compared my backup machine that the replication task sends files to and it is also showing the same difference in space used. I don't recall deleting any files let alone over 100GB worth. I have added a a few files but no more than 20GB. I have too many files to know if I am losing anything. Hopefully someone can help me understand what is going on.

Primary setup:
Gigabyte motherboard with i5-3470 and 8GB DDR3
Dell H310 raid controller with Dell firmware (Yes I know this is incorrect config.)
Eight 1TB HDDs in raid Z2 with lz4 compression. Compression ratio is 1.02

 

[tsteine]

Are you using ZFS snapshots? are old snapshots at the end of their lifecycle and being deleted, thus cleaning out the old changed data?

 

[What_Is_Computer]

I think I have the default periodic snapshot tasks going. Would windows be able to tell if snapshots are part of the used space?

 

[tsteine]

@What_Is_Computer It depends.
If you are accessing a share over the network with SMB, ZFS reports to samba how much space is free for the shared directory, that includes space used by snapshots, so the amount of space that is free (or conversely, used) respects how much free space the ZFS dataset actually has.

Though if you were to look at a single file which has x amount of revisions stored in snapshots, samba would still only report the actual size of the most recent version of the file.

I'm not entirely sure how that would interact with something like shadow copy though. so don't take this as gospel, I could be wrong.

 

[What_Is_Computer]

Ok it is probably SMB reporting the snapshots then. I appreciate your help and knowledge. Eventually I will get the hang of this.