AIX

OK. let's get back to basics.
1. make a mksysb to be able to go back in case all else fails. Possible is that this mksysb image will want two disks to reinstall to. See below.

2. Unmirrorvg does not save a copy of rootvg - it removes it. After running the command reducevg rootvg hdiskX you will have a spare disk - hdiskX.

So, now there is a spare disk.

You could do a clean install onto hdiskX - assuming the hardware support AIX 6.1 (is it Power4 or newer?). You may be missing a lot of information from the other system - but at least you know AIX installs and runs.

So, now that you know AIX 6.1 installs - then if AIX 6.1 has the files needed to support alt_disk_install from AIX 4.3.3 then use the clone option to make the rootvg copy on hdiskX (overwriting the fresh install you just did) and then continue the process to do the migration.

If AIX 6.1 does not support alt_disk_install from 4.3.3 then you will need to make a second mksysb of the current configuration (only one disk in rootvg) and when that finishes, reboot from the mysysb image and restore to the spare hdiskX.

Now you have the same AIX installed twice (clone_copy the old slow way). Now reboot again using the AIX 6.1 media and follow the migration path to update to keep the information lost by the fresh install.

I hope this is all fairly clear - AND - that it helps!

If you are talking about multibos (or alt_disk_install), you will change the bootlist when the system is up and running, then you reboot the system and it will boot off the upgraded/migrated version of OS.
After you had perform multibos operation, you will change the bootlist (hd5)

Code:

bootlist -m normal hdiskX blv=bos_hd5, where X=0,1,2,3 etc.., (root disk)

, this will change the bootlist to the one you just upgraded/migrated.

I have done it many times and it works, and you don't have to go to SMS menu to configure this.

I think the mksysb will take the multibos backup when they are mounted. ( Please correct if I am wrong).

My worry would be that if I am not able to boot with the upgrade done (and it's a pretty strong case to revert really) I am not at a prompt that I can update the bootlist. How would I achieve it then? I guess that there is maintenance mode from CD, but I would still need to know the value to set for blv Do we know what multibos will generate?

It does seem like a neat process, especially where physical disks are limited. Personally, I would never risk reducing to a single copy of any LV unless it's on externally protected disks (RAID SAN LUNs etc.) because sod's law could apply.


Thanks for any more information.

Robin

Say you upgraded and changed the bootlist, but for any reason the system ain't liking it, you can reverse the bootlist and reboot the system to go back to old version.

Now, to know which bootlist you booted off, you can do

Code:

bootlist -m normal -o, it will list you the current bootlist option

Here if you are seeing

Code:

blv

, as

Code:

hd5

, then you need to change the bootlist to

Code:

bos_hd5

or vice versa.
To change the bootlist you can use the syntax I mentioned in my previous posts.