How to get rid of an unavailable pool?

[Trond Endrestøl]

On Sat, 2 May 2020 06:15+0200, Ireneusz Pluta wrote:

> Hi group,
> 
> (Sorry if this post appears twice. The first one, initially sent from another
> email account, does not seem to appear.)
> 
> I have (or rather had) a pool like this:
> 
> $ sudo zpool status -v t
>   pool: t
>  state: UNAVAIL
> status: One or more devices are faulted in response to IO failures.
> action: Make sure the affected devices are connected, then run 'zpool clear'.
>    see: http://illumos.org/msg/ZFS-8000-HC
>   scan: none requested
> config:
> 
>         NAME                     STATE     READ WRITE CKSUM
>         t                        UNAVAIL      0     0 0
>           mirror-0               UNAVAIL      0     0 0
>             4304281762335857859  REMOVED      0     0 0  was /dev/da5
>             1909766900844089131  REMOVED      0     0 0  was /dev/da10
> 
> errors: Permanent errors have been detected in the following files:
> 
>         <metadata>:<0x0>
>         <metadata>:<0x1b>
>         t:<0x0>
> 
> That was a temporary test pool. I forgot to destroy  or at least export the
> pool before pulling these da5 and da10 drives out of the drivebay of the
> server. Now it can't be exported or destroyed, the respective zpool operations
> hust hang. How to get rid now of this pool, preferably without reboot? The da5
> and da10 are no longer available to be put back, as they have been already
> moved elsewhere, and are now part of another pool.
> 
> I guess the pool got stuck at the time of running
> /etc/periodic/security/100.chksetuid, when find operation within it tried to
> traverse into the mountpoint of the pool.
> 
> The system is FreeBSD 11.2.
> 
> Thanks
> 
> Irek

The pool might still be listed in /boot/zfs/zpool.cache. The only way 
I can think of to get rid of the old pool, is to delete this file and 
reboot. If you have more pools than your root pool, you should reboot 
to singleuser mode, mount the root fs read-write, import the 
remaining pools, and either exit the SUS shell or reboot.

-- 
Trond.