ZFS: i/o error - all block copies unavailable on large disk number machines

[Matthew Seaman]

On 23/01/2012 19:29, Steven Hartland wrote:
> Initially the zpool was just the first raidz2. Only after install
> was the second raidz2 added to increase capacity.
> 
> So what I believe has happened is the new kernel when installed
> happens to have data be located on the second raidz2 which
> consists of disks not available to the BIOS and hence results in
> "all block copies unavailable" from the boot code.

Exactly what happened to me.  You can run into this in a nasty way --
insert the drives, and expand the zpool on-line, and everything will
carry on quite happily.  Until you next reboot, when it just won't come
back.  And you can't undo the expansion of the pool: due to the
copy-on-write behaviour of ZFS even overwriting a file in-place stands a
50% chance of being written to the new vdev.

In my case, I fixed it by having a separate /boot on some USB sticks --
this was only ever accessed to read the kernel, kernel modules and
bootloader at boot time, so no worries over performance.

	Cheers,

	Matthew

-- 
Dr Matthew J Seaman MA, D.Phil.                   7 Priory Courtyard
                                                  Flat 3
PGP: http://www.infracaninophile.co.uk/pgpkey     Ramsgate
JID: matthew at infracaninophile.co.uk               Kent, CT11 9PW

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