Managing Multiple Instances of altinst_rootvg

Edit: Still good information

Originally posted August 13, 2019 on AIXchange

Chris Gibson recently tweeted this IBM Support technote on how to manage multiple instances of altinst_rootvg on AIX.

Earlier this summer Chris Gibson tweeted this IBM Support technote that explains how to manage multiple instances of altinst_rootvg on AIX.

Here’s the gist of it:

Question
What is the recommended way of managing multiple instances of altinst_rootvg and applying interim fixes to each of the clones?

Answer
This document describes the recommended preparation and process when managing multiple instances of altinst_rootvg. We will discuss the usage of the ‘-v’ flag for the ‘alt_rootvg_op’ command, applying interim fixes when cloning the rootvg and finally post-checks and FAQ.

What will this document cover?
· Creating of multiple instances of altinst_rootvg and renaming them for convenience and easy management by:
– cloning of the rootvg using the ‘alt_disk_copy’ command
– cloning and updating the rootvg using ‘alt_’ commands
– migrating the rootvg using the ‘nimadm’ command
– renaming of volume group(s) by using the ‘alt_rootvg_op’ command
· Waking up and putting back to sleep cloned/migrated disk(s)
· Applying interim fixes to the migrated and cloned disk(s)

What this document will not cover?
· Most flags used with ‘alt_’ commands
· Alternate disk clone and nimadm pre-checks and requirements
· Any NIM related operations in conjunction with ‘alt_disk_copy’
· The phases of the nimadm process
· Most flags used with the ‘nimadm’ command
· Requirements for nimadm
· Limitations for nimadm

Frequently asked questions

Q: Can I wake up 2 rootvgs at the same time and perform operations on them?
A: No. Only one rootvg can be woken up at a time.

Q: Is it possible to wake up a rootvg that is at a higher oslevel than the rootvg used to initiate the wake up?
A: No. The running system’s operating system must be a version greater than or equal to the operating system version of the volume group that undergoes the wake up.

Q: Is there a limitation of maximum clones supported?
A: No there is no limitation.

Q: Can I update one of the clones in the future to a new Service Pack or Technology level without having to boot in it?
A: Yes. First you would wake up the rootvg undergoing the update and run the following:
#alt_rootvg_op -W -d <hdisk#>
#alt_rootvg_op -C -b update_all -l /<path to updates>

Read the whole thing, then try it out on a text box. And keep in mind that supporting alt disk operations like this is another unique benefit of AIX.