Lxd containers, ZFS and snapshots

LXD
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I have got a 50GB container on my non-ZFS LXD server. Creating a single LXD snapshot of this container takes about 70 (seventy) minutes on this rather old server. If I was to add a LXD ZFS storage pool and move the container onto that, would lxd snapshots be handled by ZFS and hence be almost instant or would I still be waiting 70 or so minutes because of qcow limitations, if that’s what lxd uses for ZFS backed containers?

When creating lxd snapshots of a non-ZFS backed container, how much does the performance of the container suffer with each snapshot added, if performance does degrade? If there is a performance penalty, Is there a recommended upper limit of snapshots that can be took of any one container before performance suffers too much for it to be be worthwhile?

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ZFS should make this near instant.

Assuming your non-zfs means directory storage, then each snapshot is a full rsync of the container, which if it contains sparse files, can be extremely slow. The performance post-snapshot will not degrade as a snapshot on dir backend is just a copy of the entire container, there’s no copy on write or anything at play there, which also means they take up a lot of space.

ZFS snapshots don’t have any of those issues, they’re instant and will only use as much disk space as whatever changed later on.

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