AIX 5.3 from 64 bit to 32 bit

[hfaix]

I have been using a standard mksysb to build all AIX 5.3 (64 bit) machines in our environment, but today I found out I need to build a 32 bit machine.

Can I build a machine as 64 bit, then switch it to 32 bit? If so, how?

Thanks!

 

[kierong]

Go to the PSeries information center and search on 64bit. You can change from 64Bit to 32Bit and back again without difficulty. You can still build your machines the same way and then switch to 32Bit. Just be sure you are not running applications which require a 64Bit kernel when you change to 32Bit.

http://publib.boulder.ibm.com/infoc...t_books/rsct_man_shared_disks/am706mst12.html

 

[p5wizard]

see /usr/lpp/bos/README file:

* Installation and Enablement. The 32-bit and 64-bit kernels are
provided as part of the AIX 5L Version 5.3 base media and are
installed on all supported hardware systems. By default, the 32-bit
kernel is enabled during base system installation. However, you can
override this at installation time to enable the 64-bit kernel
through the system installation panels.

You can switch between the 32-bit and 64-bit kernels without
reinstalling the operating system.
1. Modify the /usr/lib/boot/unix directory [entry] and the /unix directory [entry] to
be a symbolic link to the binary for the desired kernel.
2. Run the bosboot command to write a new system boot image.
3. Reboot the system.

The path name of the 64-bit kernel is /usr/lib/boot/unix_64, and the
path name of the multiprocessor versions of the 32-bit kernel is
/usr/lib/boot/unix_mp.

So, to go from 64bit to 32bit kernel:

ln -f -s /unix /usr/lib/boot/unix_mp
ln -f -s /usr/lib/boot/unix /usr/lib/boot/unix_mp
bosboot -a -d /dev/hdisk0 -l /dev/hd5 # adapt if necessary
shutdown -Fr

And to go from 32bit to 64bit kernel:

ln -f -s /unix /usr/lib/boot/unix_64
ln -f -s /usr/lib/boot/unix /usr/lib/boot/unix_64
bosboot -a -d /dev/hdisk0 -l /dev/hd5 # adapt if necessary
shutdown -Fr

Note: JFS2 filesystems run better under a 64bit AIX kernel, but can run under 32bit kernel.


HTH,

p5wizard