Why is my AIX system using 32-bit kernel following system recovery?

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I have made a backup of an AIX 5.1 system running on the 32-bit kernel. I installed from this backup onto another system, for the purpose of cloning, that was a 64 bit system. After the system rebooted following the SBAdmin install the system was not using the 64-bit kernel. How does SBAdmin determine which kernel will be used following the install?

ANSWER

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The kernel in use at the time the backup is created and stored in the backup information. SBAdmin will then link to the same kernel after the installation completes. This way, if you were running a 32-bit kernel, you will still be using a 32-bit kernel, even after installing onto a 64-bit system. If you were using a 64-bit kernel, you will continue to use a 64-bit kernel. And if you were running a 64-bit kernel, but install onto a 32-bit system, we then link to the 32-bit kernel instead.

The only time you might not get the effect you expect is if you clone from a 32-bit to a 64-bit system. Some might expect to automatically link to the 64-bit kernel, but this will not happen automatically.

If you would like to change the boot kernel from 32-bit to 64-bit perform the following steps:

# ln -sf /usr/lib/boot/unix_64 /unix
# ln -sf /usr/lib/boot/unix_64 /usr/lib/boot/unix
# bosboot -a -d /dev/hdisk0
(assuming that hdisk0 contains the boot logical volume)