How to Create a Mirror From an Existing Concat/Stripe (Command Line)

This example begins with a concatenation, d1, with a mounted file system, and ends up with the file system mounted on a two-way mirror named d1.

# metastat d1
d1: Concat/Stripe
    Size: 5600 blocks
    Stripe 0:
        Device              Start Block  Dbase
        c0t0d0s1                   0     No
# metainit d2 1 1 c1t3d0s1
d2: Concat/Stripe is setup
# metainit -f d20 -m d1
d20: Mirror is setup
# umount /fs2
# metarename -x d20 d1
d20 and d1 have exchanged identities
# metastat d1
d1: Mirror
    Submirror 0: d20
      State: Okay
... 
 
d20: Submirror of d1
    State: Okay
...
# metattach d1 d2
d1: submirror d2 is attached
# metastat d1
d1: Mirror
    Submirror 0: d20
      State: Okay
    Submirror 1: d2
      State: Okay
...
# mount /fs2

The metastat command confirms that the concatenation d1 is in the "Okay" state. You use the metainit command to create a second concatenation (d2), and then to force (-f) the creation of mirror d20 from d1. You must unmount the file system before using metarename -x to switch d20 for d1; d1 becomes the top-level device (the mirror), which metastat confirms. You attach d2 as the second submirror, verify the state of the mirror with metastat, then remount the file system. Note that because the mount device for /fs2 did not change, you do not have to edit the /etc/vfstab file.