ZFS 'read-only' device / pool scan / import?

[Willem Jan Withagen]

On 2010-10-19 17:30, Karl Pielorz wrote:

> As there is such a large aspect of human error (and controller
> behaviour), I don't think it's worth digging into any deeper. It's the
> first pool we've ever "lost" under ZFS, and like I said a combination of
> the controller collapsing devices, and humans replacing wrong disks,
> 'twas doomed to fail from the start.
>
> We've replaced failed drives on this system before - but never rebooted
> after a failure, before a replacement - and never replaced the wrong
> drive :)
>
> Definitely a good advert for backups though :)

I'm running my ZFS stuff on a 3ware and an areca controller, and they 
once in a while forgot their order of disks during booting.
(the 3ware got fixed by a bios upgrade)
The areca just keeps reordering no matter how hard you like to tell it 
otherwise.

But GPT really proves useful since reallocation of disks does not result 
in a different device in the gpt directory.

eg.:
   pool: zroot
  state: ONLINE
  scrub: none requested
config:

         NAME           STATE     READ WRITE CKSUM
         zroot          ONLINE       0     0     0
           mirror       ONLINE       0     0     0
             gpt/root4  ONLINE       0     0     0
             gpt/root6  ONLINE       0     0     0

I could even migrate a disk from the 3ware controller to the std SATA 
interfaces without losing the the gpt-label.

--WjW