Expanding rootvg disk in VIO environment where 2 VIO servers have been implemented for redundancy.

This article depicts the procedure for expanding a rootvg volume group for a POWER5 LPAR where two VIO Servers have been implemented for redundancy. It also assumes that the rootvg is mirrored across both VIO Servers. This procedure is not supported by IBM, but does work.
POWER5 LPAR:
• Begin by unmirroring your rootvg and remove hdisk1 from the rootvg volume group. If there are any swap or dump devices on this disk you may need to remove them first before you can remove hdisk1 from the rootvg volume group.

• Once the disk has been removed from the rootvg, remove it from the LPAR by executing the following:
#rmdev -l hdisk1 - d

• Now you execute the bosboot command and update your bootlist now that hdisk1 has been removed and is no longer part of the system:
#bosboot -a bootlist -o -m normal hdisk0

VIO Server (where hdisk1 was created):

• Remove the device from the VIO Server using the rmdev command:
#rmdev -dev < bckcnim_hdisk1 >

• Next you will need to access the AIX* OS part of the VIO Server by executing:
#oem_setup_env

• Now you have two options: you can extend the existing logical volume or create a new one if there is more than enough disk space left. In this example I will be using bckcnim_lv. smitty extendlv and add additonal LP's or smitty mklv

• Exit out of oem_setup_env by just typing "exit" at the OS prompt.

• Now that you are back within the restricted shell of the VIO Server, execute the following command. You can use whatever device name you wish. I used bckcnim_hdisk1 just for example purposes:
#mkvdev -vdev bckcnim_lv -vadapter < vhost# > -dev bckcnim_hdisk1

POWER5 LPAR:
• Execute cfgmgr to add the new hdisk1 back to LPAR:
#cfgmgr

• Add hdisk1 back to the rootvg volume group using the extendvg or smitty extendvg.

• Mirror rootvg using the mirrorvg command or smitty mirrorvg

• Sync the mirroring process to the background and wait to complete. This is very important and must complete before dealing with what represents the hdisk0 logical volume.

• Now you must execute bosboot again and update the bootlist again:
#bosboot -a
#bootlist -o -m normal hdisk0 hdisk1