When is 'zpool offline' required?

[Freddie Cash]

On Mon, Feb 8, 2021 at 10:10 AM joe mcguckin <joe at via.net> wrote:

> I was just playing around with a test ZFS system and was running through
> replacing a bad drive and I forgot to issue a ‘zpool offline’ command.
> Everything seemed to go ok anyway. The system started resilvering, etc.
> When is ‘zpool required’? Under what conditions can I omit it?
>

If the drive is dying but still working, then using "zpool offline" is
recommended, to tell the pool to stop using the drive.  This is also handy
if there's going to be a delay between "noticed the drive is dying" and
"have a replacement drive available".

If the drive is completely dead, then most likely it will be dropped from
the pool automatically by ZFS, so "zpool offline" isn't needed.

While it's generally "better" to offline drives, ZFS is designed to
withstand drives dropping off without warning.


> Is there a dedicated mailing list for ZFS user questions?
>

There's a zfs-discuss mailing list run by the OpenZFS project.  There isn't
a FreeBSD ZFS-specific mailing list, but there is a freebsd-fs@ mailing
list for everything filesystem related (UFS, ZFS, mfs, NFS, etc).

Cheers,
Freddie