ZPOOL: Detach a submirror from a mirrored zpool -

ZPOOL: Detach a submirror from a mirrored zpool

# Tested on RHEL 6 & 7

# Even if ZFS can use individual slices or partitions, it is recommended to use whole disks.

# Having a mirrored zpool like following one

POOLNAME=my_pool

zpool status $POOLNAME
     pool: my_pool
    state: ONLINE
    scan: resilvered 65K in 0h0m with 0 errors on Tue Sep 1 16:37:43 2015
   config:

           NAME        STATE     READ WRITE CKSUM
           my_pool     ONLINE       0     0     0
             mirror-0 ONLINE       0     0     0
               sdb     ONLINE       0     0     0
               sdd     ONLINE       0     0     0
             mirror-1 ONLINE       0     0     0
               sdc     ONLINE       0     0     0
               sde     ONLINE       0     0     0

   errors: No known data errors

# we would like to detach one of the sides of the mirror

DEVICE01=/dev/sdd
DEVICE02=/dev/sde

# We detach one by one the devices from one of the sides of the mirror:

zpool detach $POOLNAME $DEVICE02

zpool status $POOLNAME
     pool: my_pool
    state: ONLINE
    scan: resilvered 65K in 0h0m with 0 errors on Tue Sep 1 16:37:43 2015
   config:

           NAME        STATE     READ WRITE CKSUM
           my_pool     ONLINE       0     0     0
             mirror-0 ONLINE       0     0     0
               sdb     ONLINE       0     0     0
               sdd     ONLINE       0     0     0
             sdc       ONLINE       0     0     0

   errors: No known data errors

zpool detach $POOLNAME $DEVICE01

zpool status $POOLNAME
     pool: my_pool
    state: ONLINE
    scan: resilvered 65K in 0h0m with 0 errors on Tue Sep 1 16:37:43 2015
   config:

           NAME        STATE     READ WRITE CKSUM
           my_pool     ONLINE       0     0     0
             sdb       ONLINE       0     0     0
             sdc       ONLINE       0     0     0

   errors: No known data errors