kern/166566: [zfs] zfs split renders 2 disk (MBR based) mirror unbootable

[George Hartzell]

The following reply was made to PR kern/166566; it has been noted by GNATS.

From: George Hartzell <hartzell at alerce.com>
To: Andriy Gapon <avg at FreeBSD.org>
Cc: hartzell at alerce.com,
    bug-followup at FreeBSD.org
Subject: Re: kern/166566: [zfs] zfs split renders 2 disk (MBR based) mirror
 unbootable
Date: Fri, 29 Jun 2012 16:33:37 -0700

 Andriy Gapon writes:
  > on 28/06/2012 00:53 George Hartzell said the following:
  > [...]
  > > I thought the following would work, but it does not.
  > > 
  > >   zpool split -R /zsplitroot zroot zsplitroot
  > >   zpool status  # shows both pools.
  > >   mount -t zfs zsplitroot /zsplitroot  # my zfs stuff doesn't auto mount
  > >   cp /boot/zfs/zpool.cache /zsplitroot/boot/zfs
  > >   perl -pi.bak -e 's|zfs:zroot|zfs:zsplitroot|' /zsplitroot/boot/loader.conf
  > >   umount /zsplitroot
  > > 
  > > It fails to mount zsplitroot.  Worse, setting vfs.zfs.debug=1 results
  > > in no additional output, just that the error is number 2.
  > > 
  > > Any idea what I'm missing?
  > 
  > 
  > /boot/zfs/zpool.cache after split contains only information about zroot.  Thus
  > it's kind of useless on zsplitroot.
  > I think that you need to do zpool import -R ... -c ... zsplitroot and copy the
  > proper cache file.
 
 I thought that adding the "-R /zsplitroot" arg to the zpool split so
 that also did the import would result in a zpool.cache file that
 contained by.  zpool status after the split shows both pool, which
 I didn't think was the case if you don't use -R.
 
 g.