Edit: I still use mksysb migrations, but not with 4.3.
Originally posted November 19, 2007 on AIXchange
During last month’s IBM System p, AIX and Linux Technical University in San Antonio, I listened to a presentation on Advanced Network Installation Manager (NIM).
One topic introduced by the presenter, IBM’s Steve Knudson, has really stuck with me. It’s called a mksysb migration, and you use NIM to implement it.
I still have customers that are running AIX 4.3. Some of your customers are, too. When the day finally comes to upgrade them, how will you do it? Will you attempt to upgrade the OS on old hardware that might not support the running of the upgraded OS? Will you just pray that your customers simply retire whatever old applications they’re running on their old hardware and old OSs to spare you from performing any migrations?
I have a better solution: Do what Steve suggests. According to his notes from the conference, the mksysb migration allows you to restore an old non-supported mksysb on POWER5 or POWER6 hardware. Once the mksysb is copied to the new hardware, it’s immediately upgraded.
This process involves booting the client machine from the NIM master server with the AIX5.3 SPOT. The NIM server restores the backlevel mksysb, then immediately migrates the mksysb to AIX5.3.
See the IBM Redbooks publication, “NIM From A to Z in AIX 5L” pages 205-216, for details.
Here’s an excerpt:
“Given that AIX 4.3 is not supported on the POWER5 platform, in the days before ‘mksysb migrations,’ the only course of action would have been to upgrade the AIX 4.3.3 system to AIX 5L V5.3 on the existing hardware (for example, the 6H1) and then clone the system via a mksysb to the new POWER5 LPAR. This process is now simplified with the mksysb migration.
“A mksysb migration allows you to move a lower level AIX system (for example, AIX 4.3.3 or AIX 5L V5.1) to POWER5 without upgrading AIX on the existing server first. Essentially you boot AIX 5L V5.3 media (in our case, we use NIM) and recover the AIX 4.3.3 or AIX 5L V5.1 mksysb image, followed by an
immediate migration to AIX 5L V5.3. This was not possible with previous versions of AIX and pSeries hardware. A mksysb migration is now the recommended way of moving unsupported hardware configurations of AIX 4.3 and AIX 5L V5.1 to new supported hardware and AIX 5L V5.3.
“The end result is that the new system will be a clone of the existing system, but will be running AIX 5L V5.3 on a POWER5 platform. The existing system remains the same (for example, running AIX 4.3). You may choose to use this method to perform a test migration of a system and certify the applications,
databases, or code against AIX 5L V5.3 on the clone before executing the real mksysb migration at some later stage.”
I’m going to try this out myself. Once I run a few tests I’ll let you know what I find.