zfs discuss - Jan 2007 - restore pool from detached disk from mirror

Hello zfs-discuss,

  I had a pool with only two disks in a mirror. I detached one disks
  and have erased later first disk. Now i would really like to quickly
  get data from the second disk available again. Other than detaching
  the second disk nothing else was done to it.

  Has anyone written such a tool in-house? I guess only vdev label was
  erased so it should be possible to do it.

  ?

-- 
Best regards,
 Robert                          mailto:rmilkowski at task.gda.pl
                                     http://milek.blogspot.com

Hello,

On 1/30/07, Robert Milkowski <rmilkowski at task.gda.pl>
wrote:
> Hello zfs-discuss,
>
>   I had a pool with only two disks in a mirror. I detached one disks
>   and have erased later first disk. Now i would really like to quickly
>   get data from the second disk available again. Other than detaching
>   the second disk nothing else was done to it.
>
>   Has anyone written such a tool in-house? I guess only vdev label was
>   erased so it should be possible to do it.
My grokking of the code confirms that the vdev labels of a detached
vdev are wiped. The vdev label contains the uber block. Without the
uber block, we can''t access the rest of the zpool/zfs data on the
detached vdev.


-- 
Regards,
Jeremy

Jeremy is correct. There is actually an RFE open to allow a "zpool
split" that would have allowed you to detach the second disk while keeping
the vdev data (and thus allowing you to pull in the data in the detached disk
using some sort of "import" type command).

Rainer
 
 
This message posted from opensolaris.org

On 1/30/07, Jeremy Teo <white.wristband at gmail.com>
wrote:
> Hello,
>
> On 1/30/07, Robert Milkowski <rmilkowski at task.gda.pl> wrote:
> > Hello zfs-discuss,
> >
> >   I had a pool with only two disks in a mirror. I detached one disks
> >   and have erased later first disk. Now i would really like to quickly
> >   get data from the second disk available again. Other than detaching
> >   the second disk nothing else was done to it.
> >
> >   Has anyone written such a tool in-house? I guess only vdev label was
> >   erased so it should be possible to do it.
>
> My grokking of the code confirms that the vdev labels of a detached
> vdev are wiped. The vdev label contains the uber block. Without the
> uber block, we can''t access the rest of the zpool/zfs data on the
> detached vdev.
On a related note: I''ve been itching to make what you want possible
also (ie detaching a vdev from a mirror and getting a zpool from via
zpool import. I''ll see what I can do over the next few weeks. I
presume you would be willing to be a tester? ;)
> Regards,
> Jeremy
>

-- 
Regards,
Jeremy

Hello Jeremy,

Wednesday, January 31, 2007, 10:21:59 AM, you wrote:

JT> On 1/30/07, Jeremy Teo <white.wristband at gmail.com> wrote:

JT> On a related note: I''ve been itching to make what you want
possible
JT> also (ie detaching a vdev from a mirror and getting a zpool from via
JT> zpool import. I''ll see what I can do over the next few weeks. I
JT> presume you would be willing to be a tester? ;)

You kidding? Of course :)


-- 
Best regards,
 Robert                            mailto:rmilkowski at task.gda.pl
                                       http://milek.blogspot.com