[Libguestfs] libguestfs and zfs-fuse

[Pino Toscano]

On Tuesday 04 February 2014 09:54:58 Richard W.M. Jones wrote:
> On Mon, Feb 03, 2014 at 09:14:09PM +0000, Richard W.M. Jones wrote:
> > On Mon, Feb 03, 2014 at 03:29:37PM -0500, Andre Goree wrote:
> > > Ahhh, understood.  I do have have an image I can provide that was
> > > installed onto and MBR layout (seemed the easiest for libguestfs
> > > to
> > > understand, GPT is preferred if libguestfs works well with it, but
> > > that's another matter I can look into later).  Standby let me
> > > clean
> > > it up a bit and I'll get it to you -- I'll put it on my box and
> > > send
> > > ya a link offlist.
> > 
> > Yes it would be useful to have this image.  Either MBR or GPT
> > should work equally well.
> 
> FYI Andre sent me a disk image:
> 
> $ qemu-img info FreeBSD_ZFS-test.qcow2
> image: FreeBSD_ZFS-test.qcow2
> file format: qcow2
> virtual size: 1.0G (1073741824 bytes)
> disk size: 1.0G
> cluster_size: 65536
> 
> $ guestfish --ro -a FreeBSD_ZFS-test.qcow2
> 
> Welcome to guestfish, the guest filesystem shell for
> editing virtual machine filesystems and disk images.
> 
> Type: 'help' for help on commands
>       'man' to read the manual
>       'quit' to quit the shell
> 
> ><fs> run
> ><fs> list-filesystems
> ><fs> list-partitions
> 
> /dev/sda1
> 
> ><fs> file /dev/sda1
> 
> ; partition 4: ID=0xa5, active, starthead 0, startsector 0, 50000
> sectors
> ><fs> vfs-type /dev/sda1
> 
> zfs_member
> 
> I tried opening it with virt-rescue, but for some reason the zfs-fuse
> daemon would not start, and hence other commands such as zpool didn't
> work.

I've taken a quick look at this, and got a bit more with:
  ><rescue> ln -s ../run/lock /var/lock
  ><rescue> zfs-fuse-helper start
  Starting zfs-fuse: [  OK  ]
  Immunizing zfs-fuse against OOM kills[  OK  ]
  Mounting zfs partitions: [  OK  ]
and after this the zpool/zfs commands were usable.

Just note that:
a) the first command is not needed now with the newly released
   development version libguestfs 1.25.33
b) I couldn't mount the image you provided, since it was created with
   versions of zpool and zfs greater than what zfs-fuse currently
   supports (it seems not having been updated in a while...)
so even if we automate somehow the starting of the zfs-fuse helper and 
the handling of zpool/zfs, I'm not sure it could be actually useful with 
a zfs-fuse not supporting recent versions.
(To have a test partition with ZFS, I had to create it on a 
Debian/kFreeBSD 6.0 (oldstable), as even Debian/kFreeBSD 7 (stable) had 
"too new" zfs stuff for zfs-fuse.)

-- 
Pino Toscano