AIX Disk Management

On the AIX Box do a man on these commands

# man mklv

# man extendvg

# man reducevg

Also if you want further general reading on the subject

http://www.redbooks.ibm.com/redbooks/pdfs/sg245432.pdf

Procedure:

The following steps assume that you have rootvg contained on hdisk0 and is attempting to mirror the rootvg to a new disk hdisk1.

1. Physically add new drive to volume group and reboot the machine. If it is a scsi drive, make sure you have a scsi slot available. If you do not know how to do this, let me know.
2. Disable QUORUM, by running the following:

chvg -Qn rootvg

3. Mirror the logical volumes that make up the AIX operating system by the following command:

mklvcopy hd1 2 hdisk1 # /home file system
mklvcopy hd2 2 hdisk1 # /usr file system
mklvcopy hd3 2 hdisk1 # /tmp file system
mklvcopy hd4 2 hdisk1 # / (root) file system
mklvcopy hd5 2 hdisk1 # blv, boot logical volume
mklvcopy hd6 2 hdisk1 # paging space
mklvcopy paging00 2 hdisk1 # paging space
mklvcopy hd8 2 hdisk1 # file system log
mklvcopy hd9var 2 hdisk1 # /var file system
mklvcopy met 2 hdisk1 # /file system log
mklvcopy page 2 hdisk1 # file system log
mklvcopy data 2 hdisk1 # file system log

** Run this step later in the day - it will cause system slowness.

** 4. Synchronize the newly created mirrors by running this command:

syncvg -v rootvg

5. Bosboot to initialize all boot records and devices by using this command:

bosboot -a

6. Initialize the boot list by using this command:

bootlist -m normal hdisk0 hdisk1

7. Shutdown and reboot the system:

shutdown -Fr

This is so that the "Quorum OFF" function takes effect.
Note: This procedure works and I used it two months ago. I have IBM RS6000 system and used it to add a second drive to it. Now I have two mirrored drives.