Fwd: ZFS

[Nikos Vassiliadis]

Hi everybody,

While trying to rename a zpool from zroot to vega,
I ended up in this strange situation:
nik at vega:~ % zfs list -t all
NAME                 USED  AVAIL  REFER  MOUNTPOINT
vega                1.83G  34.7G    96K  /zroot
vega/ROOT           1.24G  34.7G    96K  none
vega/ROOT/default   1.24G  34.7G  1.24G  /
vega/tmp             120K  34.7G   120K  /tmp
vega/usr             608M  34.7G    96K  /usr
vega/usr/home        136K  34.7G   136K  /usr/home
vega/usr/ports        96K  34.7G    96K  /usr/ports
vega/usr/src         607M  34.7G   607M  /usr/src
vega/var             720K  34.7G    96K  /var
vega/var/audit        96K  34.7G    96K  /var/audit
vega/var/crash        96K  34.7G    96K  /var/crash
vega/var/log         236K  34.7G   236K  /var/log
vega/var/mail        100K  34.7G   100K  /var/mail
vega/var/tmp          96K  34.7G    96K  /var/tmp
zroot               1.83G  34.7G    96K  /zroot
zroot/ROOT          1.24G  34.7G    96K  none
zroot/ROOT/default  1.24G  34.7G  1.24G  /
zroot/tmp            120K  34.7G   120K  /tmp
zroot/usr            608M  34.7G    96K  /usr
zroot/usr/home       136K  34.7G   136K  /usr/home
zroot/usr/ports       96K  34.7G    96K  /usr/ports
zroot/usr/src        607M  34.7G   607M  /usr/src
zroot/var            724K  34.7G    96K  /var
zroot/var/audit       96K  34.7G    96K  /var/audit
zroot/var/crash       96K  34.7G    96K  /var/crash
zroot/var/log        240K  34.7G   240K  /var/log
zroot/var/mail       100K  34.7G   100K  /var/mail
zroot/var/tmp         96K  34.7G    96K  /var/tmp
nik at vega:~ % zpool status
   pool: vega
  state: ONLINE
   scan: scrub repaired 0 in 0h0m with 0 errors on Mon May 15 01:28:48 2017
config:

	NAME        STATE     READ WRITE CKSUM
	vega        ONLINE       0     0     0
	  vtbd0p3   ONLINE       0     0     0

errors: No known data errors

   pool: zroot
  state: ONLINE
   scan: scrub repaired 0 in 0h0m with 0 errors on Mon May 15 01:28:48 2017
config:

	NAME        STATE     READ WRITE CKSUM
	zroot       ONLINE       0     0     0
	  vtbd0p3   ONLINE       0     0     0

errors: No known data errors
nik at vega:~ %
-------------------------------------------

It seems like there are two pools, sharing the same vdev...

After running a few commands in this state, like doing a scrub,
the pool was (most probably) destroyed. It couldn't boot anymore
and I didn't research further. Is this a known bug?

Steps to reproduce:
   install FreeBSD-11.0 in a pool named zroot
   reboot into a live-CD
   zpool import -f zroot vega
   reboot again

Thanks,
Nikos

PS:
Sorry for the cross-posting, I am doing this to share to more people
because it is a rather easy way to destroy a ZFS pool.