How to Create a Trans Metadevice From an Existing Metadevice (Command Line)

This example begins with a mirror, d1, with a mounted file system, and ends up with the file system mounted on a trans device named d1.

# metastat d1
d1: Mirror
    Submirror 0: d20
      State: Okay        
    Submirror 1: d2
      State: Okay        
...
# umount /fs2
# metainit d21 -t d1
d21: Trans is setup
# metarename -f -x d21 d1
d21 and d1 have exchanged identities
# metastat d1
d1: Trans
    State: Detached
    Size: 5600 blocks
    Master Device: d21
...
# metattach d1 d0
d1: logging device d0 is attached
# mount /fs2

The metastat command confirms that the mirror d1 is in the "Okay" state. You must unmount the file system before using the metainit command to create the trans device d21, with d1 as the master. The metarename -f -x command forces the switch of d21 and d1; d1 is now the top-level trans metadevice, as confirmed by the metastat command. A logging device d0 is attached with the metattach command. You then remount /fs2. Note that because the mount device for /fs2 has not changed (it is still d1), you do not have to edit the /etc/vfstab file.