Howto Unmirror a File System That Cannot Be Unmounted Solaris 10

Use this task to unmirror file systems, including root (/), /usr, /opt, and swap, that cannot be unmounted during normal system operation.

1. Make sure that you have root privilege and that you have a current backup of all data.
2. Verify that at least one submirror is in the Okay state.

# metastat mirror

3. Detach the submirror that will continue to be used for the file system.

# metadetach mirror submirror

4. Use one of the following commands, depending the file system you want to unmirror:
   
   
   
   • For the /usr, /opt, or swap file systems, change the file system entry in the /etc/vfstab file to use a non-Solaris Volume Manager device (slice).
   
   
   • For the root (/) file system only: run the metaroot command.

# metaroot rootslice

5. Reboot the system.

# reboot

6. Clear the remaining mirror and submirrors.

# metaclear -r mirror

Example Unmirroring the root (/) File System

# metastat d0
d0: Mirror
Submirror 0: d10
State: Okay
Submirror 1: d20
State: Okay
Pass: 1
Read option: roundrobin (default)
Write option: parallel (default)
Size: 40541184 blocks (19 GB)

d10: Submirror of d0
State: Okay
Size: 40541184 blocks (19 GB)
Stripe 0:
Device Start Block Dbase State Reloc Hot Spare
c0t0d0s0 0 No Okay Yes

d20: Submirror of d0
State: Okay
Size: 40541184 blocks (19 GB)
Stripe 0:
Device Start Block Dbase State Reloc Hot Spare
c0t1d0s0 0 No Okay Yes

# metadetach d0 d20
d0: submirror d20 is detached

# metaroot /dev/dsk/c0t0d0s0

# reboot

# metaclear -r d0
d0: Mirror is cleared
d10: Concat/Stripe is cleared

# metaclear d20
d20: Concat/Stripe is cleared

Example Unmirroring the swap File System

# metastat d1
d1: Mirror
Submirror 0: d11
State: Okay
Submirror 1: d21
State: Okay

# metadetach d1 d21
d1: submirror d21 is detached

Edit the /etc/vfstab file to change the entry for swap from metadevice to slice name

# vi /etc/vfstab

In this example, the /etc/vfstab file contains the following entry for the swap file system:

/dev/md/dsk/d1 - - swap - no -

Change the entry to read as follows:

/dev/dsk/c0t0d0s1 - - swap - no -

# reboot

# metaclear -r d1
d1: Mirror is cleared
d11: Concat/Stripe is cleared

# metaclear d21
d21: Concat/stripe is cleared