How to add a mirror disk back to VxVM

I have 3 disks which are part of the mirror group.

root@myserver # vxdisk list | grep ^c
c1t0d0s2 sliced rootdisk rootdg online
c1t1d0s2 sliced rootmirror1 rootdg online
c2t0d0s2 sliced - - online
c2t1d0s2 sliced - - online

Naming conventions:
- rootdisk
- rootmirror1
- rootmirror2
- rootmirror3

Now i want to add the mirror back. We are going to attach back device c2t0d0 into the rootdg disk group.

Always run the command vxdisk -ht to check what is the actual volume name to attach the disk to.

Setup the disk
root@myserver # vxdisksetup -if c2t0d0 (for VxVM 3.5)
root@myserver # vxdisksetup -if c2t0d0 format=sliced (for VxVM 4.0)
root@myserver # /usr/lib/vxvm/bin/vxdisksetup -if c2t0d0 format=sliced (for VxVM 4.1)

Add the disk into rootdg.
root@myserver # vxdg -g rootdg adddisk rootmirror2=c2t0d0

Mirror each of the partitions. Here i throttle the synchronisation speed to have less performance impact on the server.
root@myserver # vxassist -o slow=1500 -g rootdg mirror rootvol rootmirror2 &
root@myserver # vxassist -o slow=1500 -g rootdg mirror opt rootmirror2 &
root@myserver # vxassist -o slow=1500 -g rootdg mirror swapvol rootmirror2 &
root@myserver # vxassist -o slow=1500 -g rootdg mirror usr rootmirror2 &
root@myserver # vxassist -o slow=1500 -g rootdg mirror var rootmirror2 &

To monitor the progress of synchronisation.
root@myserver # vxtask list
TASKID PTID TYPE/STATE PCT PROGRESS
166 ATCOPY/R 07.88% 0/25166079/1982464 PLXATT opt opt-01
167 ATCOPY/R 25.29% 0/4194828/1060864 PLXATT swapvol swapvol-01
168 ATCOPY/R 15.13% 0/4194828/634880 PLXATT usr usr-01
169 ATCOPY/R 02.82% 0/16779312/473088 PLXATT var var-01