Hot Migrate Root Volumes in AIX

AIX is one of the few OSes that, out of the 'box', can replace boot disks while the OS is running without an outage.  Of course, the standard disclaimers apply... namely, test this on a non-production LPAR and make sure you have backups.  This is extremely helpful for storage array migrations (bringing an LPAR under a SVC, for example) and general maintenance.

If you’re running under VIO Servers, it even allows complete cleanup to occur online.  I recommend a reboot at the end to be safe, but it really isn't necessary.

Assumptions:  All the target disks are currently configured on the LPAR and are not in any volume groups.

Step 0: MAKE SURE TO HAVE A CURRENT MKSYSB AND BACKUP.

Step 1: Replace an old root hdisk with the new one. If this fails due to the destination disk being smaller, go to the alternate instructions below

$ replacepv OLDDISK1 NEWDISK1

0516-1011 replacepv: Logical volume hd5 is labeled as a boot logical volume.

0516-1232 replacepv:

NOTE: If this program is terminated before the completion due to

a system crash or ctrl-C, and you want to continue afterwards

execute the following command

replacepv -R /tmp/replacepv385038

0516-1011 replacepv: Logical volume hd5 is labeled as a boot logical

volume.

Step 2: Verify that the old disk is not defined to any volumegroups:

$ lspv

OLDDISK1 00007690a14xxxxx None

NEWDISK1 00007690a14xxxxx rootvg  active

OLDDISK2 00007690913xxxxx rootvg  active

Step 3: Add the boot image to the new disk:

$ bosboot -ad NEWDISK1

bosboot: Boot image is 30441 512 byte blocks.

Step 4: Repeat steps 1-3 for the second root disk (if replacing both

root disks)

Step 5: Adjust the bootlist

$ bootlist -om normal  NEWDISK1 NEWDISK2

$ bootlist -om service NEWDISK1 NEWDISK2

Step 6: Remove the old hdisks.

$ rmdev -dl OLDHDISK

Step 7: Remove the old disk mappings from the VIO Server if applicable.

$ rmdev -dev OLDMAPPING

Step 9: Run savebase

$ savebase

Alternate Instructions

Step A1: Place the replacement hdisks into the volumegroup:

extendvg rootvg NEWDISK

Step A2: Migrate the disks (you must have PPs sufficient to migrate the

disk):

migratepv OLDDISK NEWDISK

Step A3: Validate that there is no data on the old disk

lspv -l OLDDISK

Step A4: Remove the OLDDISK from the Volumegroup

reducevg rootvg OLDDISK

Step A5: Add the boot image to the new disk:

$ bosboot -ad NEWDISK1

Step A6: Repeat steps A1-A5 for the second root disk.

Step A7: Continue with step 5 above (namely, adjust the bootlist, cleanup left over disks, and savebase).