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

[Steven Hartland]

----- Original Message ----- 
From: "Matthew Seaman" 
> Even if you do split up your pool into vdevs using 8 drives, you will
> still run into the problem with zfs being unable to assemble the pool
> unless it sees all of the drives in it.
>
> Interesting that this only appeared as part of a minor kernel update.
> I ran into this myself with 8-STABLE, no indication that there was a fix
> possible by juggling kernels.

Indeed this was nothing to do with the changes in the kernel its
purely down to which disks the physical copies of the data lives
on within the boot zpool, at least that's what I believe is the key
here.

For reference the layout here is the following:-
  pool: tank2
 state: ONLINE
 scrub: none requested
config:

NAME                                            STATE     READ WRITE CKSUM
tank2                                           ONLINE       0     0     0
  raidz2                                        ONLINE       0     0     0
 gptid/aad3bd9f-05a2-11e1-8d4a-0025903b854c  ONLINE       0     0     0
 gptid/abbe61d0-05a2-11e1-8d4a-0025903b854c  ONLINE       0     0     0
 gptid/aca6dba7-05a2-11e1-8d4a-0025903b854c  ONLINE       0     0     0
 gptid/ad90c2ba-05a2-11e1-8d4a-0025903b854c  ONLINE       0     0     0
 gptid/ae773314-05a2-11e1-8d4a-0025903b854c  ONLINE       0     0     0
 gptid/af5dea39-05a2-11e1-8d4a-0025903b854c  ONLINE       0     0     0
  raidz2                                        ONLINE       0     0     0
 da0p1                                       ONLINE       0     0     0
 da1p1                                       ONLINE       0     0     0
 da2p1                                       ONLINE       0     0     0
 da3p1                                       ONLINE       0     0     0
 gptid/c21396ba-05a5-11e1-bce9-0025903b854c  ONLINE       0     0     0
 gptid/c21b30b9-05a5-11e1-bce9-0025903b854c  ONLINE       0     0     0
cache
  ada0p3                                        ONLINE       0     0     0
  ada1p3                                        ONLINE       0     0     0
spares
  gptid/4eb3ef4c-05a6-11e1-bce9-0025903b854c    AVAIL   
  gptid/c2ba092d-05a5-11e1-bce9-0025903b854c    AVAIL   

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.

    Regards
    Steve



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