zfs discuss - Apr 2008 - zfs concatenation to mirror

Hi,

Is it possible to convert a zfs pool from a concatenation of 2 disks to
a 2 way mirror without backing up the data, re-creating the pool and
restoring it. i.e 

diskA,diskB ----> mirror(diskA,diskB)

Thanks,

Jeff

Jeff,

No easy way exists to convert this configuration to a mirrored
configuration currently.

If you had two more disks, you could use zpool attach to create
a two-way, two disk mirror. See the output below.

A more complicated solution is to create two files that are the size of
your existing disks, attach them as mirrors, and detach the old
disks. Next, use zpool replace to replace the files with the previous 
disks. You would need to have enough disk space outside of the existing
pool to create the "simulated disks" with files.

Cindy

# zpool create tank c1t2d0 c1t4d0
# zpool status tank
   pool: tank
  state: ONLINE
  scrub: none requested
config:

         NAME        STATE     READ WRITE CKSUM
         tank        ONLINE       0     0     0
           c1t2d0    ONLINE       0     0     0
           c1t4d0    ONLINE       0     0     0

errors: No known data errors
# zpool attach tank c1t4d0 c1t5d0
# zpool status tank
   pool: tank
  state: ONLINE
  scrub: resilver completed with 0 errors on Fri Apr 11 13:32:20 2008
config:

         NAME        STATE     READ WRITE CKSUM
         tank        ONLINE       0     0     0
           c1t2d0    ONLINE       0     0     0
           mirror    ONLINE       0     0     0
             c1t4d0  ONLINE       0     0     0
             c1t5d0  ONLINE       0     0     0

errors: No known data errors
# zpool attach tank c1t2d0 c1t6d0
# zpool status tank
   pool: tank
  state: ONLINE
  scrub: resilver completed with 0 errors on Fri Apr 11 13:33:21 2008
config:

         NAME        STATE     READ WRITE CKSUM
         tank        ONLINE       0     0     0
           mirror    ONLINE       0     0     0
             c1t2d0  ONLINE       0     0     0
             c1t6d0  ONLINE       0     0     0
           mirror    ONLINE       0     0     0
             c1t4d0  ONLINE       0     0     0
             c1t5d0  ONLINE       0     0     0

errors: No known data errors


Jeff Walker wrote:
> Hi,
> 
> Is it possible to convert a zfs pool from a concatenation of 2 disks to
> a 2 way mirror without backing up the data, re-creating the pool and
> restoring it. i.e 
> 
> diskA,diskB ----> mirror(diskA,diskB)
> 
> Thanks,
> 
> Jeff
> 
> 
> _______________________________________________
> zfs-discuss mailing list
> zfs-discuss at opensolaris.org
> http://mail.opensolaris.org/mailman/listinfo/zfs-discuss