TrueNAS 12 RC1, using zstd, will snapshots use zstd?

[diskdiddler]

This is maybe a really silly question but what compression (if any!) is used on snapshots to further reduce disk space?

You'll note, I've only converted 1 zvol, so far (second last one, UbuntuVM)
Many automated snapshots, should be taken of it by my schedule - will those snapshots also be compressed, if so, what compression method?
OR do I need to convert above that to get snapshots compressing?

 

[morganL]

Same compression as was used when the data was originally written. .. it is still the same data.

 

[diskdiddler]

Oh yes of course that makes sense.


I have an issue now, where I have some FILESYSTEM (datasets) as a share on another pool entirely.
I would like to compress it - it's 2TB of data.

What's the best way, now that I've upgraded the pool to recompress the whole thing?
Can I use zfs send / recv like I did the zvols for the VMs?

 

[morganL]

ZFS send will send compressed data in original form... and there is no option (I know of) for recompressing it with zfs receive.

rsync would let the files be recompressed... or you could just copy the files.

 

[ornias]

@morganL
send-rec does recompress actually. well, to be clear, not actually the send-rec, writhing the send snapshot to disk using rec does. (I know because I just migrated my datasets and it has increased compression ratio.)
The trick is to set the send dataset to zstd and then use send-rec locally, it should result in a much higher compression ratio