Check
and Determine if rootvg is Mirrored
In
mirror mode, each logical volume in rootvg such as filesystems “/”, “/usr”,
“/var”, “/tmp”, “/home”, “/opt” and default boot, paging and jfslog LVs should
be mirrored. In AIX, mirrorvg will create additional copy of image for all
logical volumes in the volume group.
Use
the following command to check if a rootvg is mirrored:
#
lsvg -l rootvg
If
the output shows that for each LP there are 2 PPs then its mirrored.
Check
and Determine Which Disks the Mirrored rootvg is Located
For
each logical volume (LV) name listed in output of “lsvg -l rootvg” command, run
the following command:
#
lslv -m
The
output date will tell you on which disk each copy of each logical partitions
for each LV.
Unmirror
rootvg
Important:
The following instructions have the risk of making your AIX system unbootable
or corrupting the data. So make you have advanced system administration
experience before running the process of unmirroring.
To
unmirror the root volume group (rootvg), follow the steps below (scenario:
rootvg is contained on hdisk01 and mirrored onto hdisk11, and the steps will
remove the mirror on hdisk11 (regardless of the disk from which you previously
booted)):
To unmirror the
rootvg from hdisk11, enter the following command:
unmirrorvg
rootvg hdisk11
This
command turns quorum back on for rootvg. When unmirrorvg is executed, the
default COPIES value for each logical volume becomes 1.
To update the
booted disk link, enter the following command:
ln
-f /dev/rhdisk01 /dev/ipldevice
To reduce the
disk out of rootvg, type the following command:
reducevg
rootvg hdisk11
To initilize the
boot record of the remaining disk again, enter the following command:
bosboot
-a -d /dev/hdisk01
bosboot
command is a must to initialize the boot record on the remaining disk hdisk01
again.
To modify the
boot list to remove the unmirrored disk, type the following command:
bootlist
-m normal hdisk01
bootlist
command is a must so that the system only boots to the disk remaining (hdisk01)
in rootvg.
Restart AIX
machine, as unmirroring turns quorum back on for rootvg, a reboot is required for
this to take effect.
Note:
The reducevg command in step 3 will fail if there are non-mirrored logical
volumes such as raw logical volumes and system dump devices on the disk.