I've had a few drives fail on my ZFS for Linux fileserver and wondered why my hot spares weren't automatically kicking in, and this is why.
On Linux, if you don't use the zed script that's referenced in that Github issue above and just replace a failing drive manually, a hot spare is worse than useless, because you need to remove the hot spare from the array before you can use it with a manual replace operation.
The nice zfs built-in autoreplace functionality doesn't work on Linux or FreeNAS. You need some scripting/external tooling to do the equivalent. See
https://github.com/zfsonlinux/zfs/issues/2449
https://forums.servethehome.com/index.php?threads/zol-hotspa...
I've had a few drives fail on my ZFS for Linux fileserver and wondered why my hot spares weren't automatically kicking in, and this is why.
On Linux, if you don't use the zed script that's referenced in that Github issue above and just replace a failing drive manually, a hot spare is worse than useless, because you need to remove the hot spare from the array before you can use it with a manual replace operation.