How to Unmirror a File System and Retain the Mount Device (Command Line)

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

# metastat d1
d1: Mirror
    Submirror 0: d20
      State: Okay        
    Submirror 1: d2
      State: Okay        
    Pass: 1
...
# umount /fs2
# metarename -x d1 d20
d1 and d20 have exchanged identities
# metastat d20
d20: Mirror
    Submirror 0: d1
      State: Okay        
    Submirror 1: d2
      State: Okay        
...
 
# metadetach d20 d1
d20: submirror d1 is detached
# metaclear -r d20
d20: Mirror is cleared
d2: Concat/Stripe is cleared
# mount /fs2

The metastat command confirms that mirror d1 is in the "Okay" state. This file system is unmounted before exchanging the mirror d1 and its submirror d20. This makes the mirror d20, as confirmed by metastat. Next, d1 is detached from d20, then mirror d20 and the other submirror, d2 are deleted. Finally, /fs2 is remounted. Note that because the mount device for /fs2 did not change, the /etc/vfstab file does not require editing.