my procedure

[Ceesjan van Hattum]

Staring with 2 mirrored-disks in vg00.
1. Insert 3rd disk
2. ioscan -fCdisk
3. insf -H 14/0/0.3
4. dd if=/dev/null of=/dev/dsk/c0t3d0 bs=1024k
5. vgextend /dev/vg00 /dev/dsk/c0t3d0
6. mkboot -l /dev/dsk/c0t3d0
7. lvlnboot -r /dev/vg00/lvol3
8. lvlnboot -b /dev/vg00/lvol1
9. lvlnboot -s /dev/vg00/lvol2
10. lvlnboot -d /dev/vg00/lvol2
11. lvlnboot -R
12. for LVOL in `vgdisplay -v vg00 | grep lvol | awk '{print $3}'1
do
echo "lvextend $LVOL"
lvextend -m 2 $LVOL /dev/dsk/c0t3d0
done
13. lvlnboot -v

..reducing is not to difficult either...

[Ceesjan van Hattum]

PLEASE FORGET THIS ONE...
It was a REPLY not a new posting...
Sorry sorry, do not reply to this one...
Ceesjan

[A. Clay Stephenson]

You are certainly missing a pvcreate (-B) command. I have no idea what the dd is for unless you are confirming the existence of the device node.

[S.K. Chan]

You missed a step, after "mkboot -l" ..
# mkboot -a "hpux -lq" /dev/rdsk/c0t3d0
==> Add AUTO file in boot LIF area, "lq" option is to bypass quorum check.

And, correct me if I'm wrong, don;t you just want to lvextend 1 mirror copy to c0t3d0 instead of 2 ?