Did zpool offline, then reboot, now "freebsd zfs i/o error - all block copies unavailable"

[Tim Bishop]

I suspected one of my disks (in a zpool mirror) had a problem, so I
thought I'd test this out by offlining the disk and rebooting.

Unfortunately this failed during the reboot with the following error:

freebsd zfs i/o error - all block copies unavailable

A search of the archive suggests people have hit this before, but not in
the same circumstance (I think).

I figured the pool being degraded might be the issue, so I booted from a
livecd and detatched the offlined disk leaving the pool in a good state.
Rebooted again but the same problem occured.

I'm now back in the livecd reattaching the disk, but this'll take a long
time (ETA 24h). Fingers crossed it works!

Whilst I wait, does anybody have any ideas what went wrong?

Tim.

-- 
Tim Bishop
http://www.bishnet.net/tim/
PGP Key: 0x5AE7D984