AIX Tip of the Week

Booting Multiple Versions of AIX

Audience: System Administration

Date: April 7, 2001

The AIX "bootlist" command can be used to select the boot disk. This is useful if you want to test different AIX levels on the same system.

For example, assume hdisk0 has AIX 4.2.1 installed and hdisk1 AIX 4.3.3 installed. Use one of the following "bootlist" commands** to select which version will come up on the next reboot:

bootlist -m normal hdisk0 # Reboots to AIX421
bootlist -m normal hdisk1 # Reboots to AIX433

The second disk can be installed from CD, a "mksysb" tape, or using AIX 4.3's "alt_disk_install" capability. Both CD and mksysb installs require downtime. The "alt_disk_install" allows you to install the second disk from a "mksysb" or clone your existing OS while the system is running

** Comment: In practice, I recommend the following "bootlist" syntax which specifies that if hdisk0 fails to boot, try booting from hdisk1, then tape, and finally CD ROM.

bootlist -m normal hdisk0 hdisk1 rmt cd

Bruce Spencer,