Re: reanimate ZFS pool after disk cloning and host changing

On Thu, Oct 11, 2007 at 08:43:40PM +0200, Ralf S. Engelschall wrote:
> I've a FreeBSD 7-CURRENT (as of 2007-10-09) running in a VirtualBox
> virtual machine and with all filesystems except /boot on ZFS. Now that
> we switched to 7.0-PRERELEASE and 8-CURRENT I today created another
> virtual machine and just cloned the disks (with "vboxmanage clonevdi",
> but it doesn't matter here).
> 
> When I then booted the new virtual machine with the cloned disks, the
> root filesystem couldn't be mounted during boot via "zfs:zp1/root" as
> the ZFS pool "zp1" is no longer available.
> 
> So I booted into the Fixit environment from
> "7.0-CURRENT-200709-i386-disc1.iso" and tried "zpool import". It was
> able to detect the pool on device ad0s1f. The problem just is that the
> hostid has changed (which is correct), so I thought I just have to
> re-import the ZFS pool with "zfs import -R /zp1 -f zp1". This still
> worked just fine: all filesystem were available under temporary /zp1
> now (I had to use this alternative root or the Fixit environment is
> immediately dead). But once I then reboot into the system, the ZFS pool
> is again not found via "zfs:zp1/root"!
> 
> In tried multiple times with various ways in the Fixit environment:
> "zfs import zp1" is denied because the hostid is different, "zfs import
> -f zp1" does the trick (although breaks the Fixit environent) but
> after reboot the ZFS pool again gone, "zfs import -R /zp1 -f zp1" does
> also the trick but here again the ZFS pool is gone after reboot.
> 
> So, the silly question is: what is the correct way to reanimate a ZFS
> pool after the host has changed, so that one can again directly boot
> from from one of its filesystems (here "zp1/root")?

Is /boot/zfs/zpool.cache up to date after importing the pool? If your
seperate /boot filesystem isnt mounted when you import then you will
need to overwrite it manually.


Andrew