Q: altinst_rootvg and old_rootvg: Will you see them?
A: it depends on how you've installed the second OS instance.
Example
AIX 7.1 on hdisk1
Empty hdisk2
Situation 1:
You make a clone (smit or alt_disk_clone) to hdisk2.
-You wil see this clone as altinst_rootvg
You reboot from this disk (bootlist -m normal hdisk2; reboot)
-You see hdisk2 as rootvg and hdisk1 as old_rootvg
((If you again reboot from hdisk1 than you again will see hdisk1 as rootvg and hdisk2 as altinst_rootvg and so on)).
OK, you need AIX 7.2
So, you boot from USB/DVD and update AIX on hdisk2 to AIX 7.2
What VGs will you see after the upgrade?
The same: altinst_rootvg or old_rootvg, depends on which disk is active rootvg now.
Situation 2:
You boot from USB/DVS and make a New Install AIX 7.2 on hdisk2.
No any clones before!
In such case you will see the second disk as empty. Because the current AIX doen't know anything about the content at the second disk. Really all data will stay there, don't try to importvg (!) Just change the bootlist, reboot and you will see it.
It's because the info about VG stays not only on the disks, but also in the AIX ODM.
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Now it's my turn:
What if, in the same example, you:
1. make a clone to hdisk2.
2. boot from external media.
3. Install New AIX 7.2 to hdisk2.
Which VG will you see when you will boot from hdisk1 or hdisk2?
I know the answer. Do you?
If not - THINK!
Want to learn more - ask.
With best regards
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Dmitry Mironov
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Original Message:
Sent: Wed January 20, 2021 02:44 AM
From: Olawole Adetayo
Subject: AIX dual boot
It is very possible using alternative boot disk. It means that you will have rootvg and alt_rootvg in the systems which has to be labelled as AIX7.1 and AIX7.2 depending on the active OS disks.
The challenge here is that getting to either of the OS version, the system has to be rebooted by changing some boot disk list which must follow some steps..
bosboot -ad /dev/diskn
bootlist -m normal /dev/diskn
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Olawole Adetayo
Original Message:
Sent: Tue January 19, 2021 02:53 AM
From: Dmitry Mironov
Subject: AIX dual boot
Yes, it's possible.No limitations, just don't import the alternative rootvg. If you will do it it will not be bootable anymore because AIX will rename LVs.
So just be careful, active AIX will see the second disk as an empty one.
It doesn't matter which load source have you used: DVD, USB, Network.
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Dmitry Mironov
Original Message:
Sent: Mon January 18, 2021 12:03 PM
From: Nilabja Haldar
Subject: AIX dual boot
Client wants to do dual boot for different versions of AIX without virtualization/HMC. Like suppose he has 1 partition with 2 disks. In 1 disk he install AIX 7.1 and in other disk he install AIX 7.2. Now he will boot AIX 7.1 sometime and AIX 7.2 in some other time. Is this possible and is there any limitation or restrictions? Also the configuration does not currently include a DVD drive. Would they be able to install AIX from a USB drive and avoid the need for the DVD drive in the configuration ?
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Nilabja Haldar
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