Regarding mirroring of alternate rootvg

But normally, these alt_rootvg will not be activated by default. So whether the above commands can be executed even if the alt_rootvg is not enabled or should it be enabled first.

Virgo

OK,

so at which point in the alternate disk installation process are you right now?

You're right, you cannot work with the alternate_vg at wish, at every point in the process.
So in other words, what exactly did you do up to now?

wmp

Actually, I have not created the alt rootvg yet, I am just getting prepared for the activity scheduled tomorrow night. But I will start the alternate disk installation in the morning tomorrow. The scenario is this is the ERP Database server which is having 2 disks (hdisk472 and hdisk473), I will break the mirror and start alt disk install on hdisk0 (spare disk) and remirror hdisk473. This is to prepare for TL-12 upgrade on the system. So hdisk0 will have old OS i.e. TL10, but I need to keep the mirror copy of that also, for that i have hdisk1(spare), thats why I was asking the procedure.

virgo

First, why would you break the mirror? You do have a spare disk (even two!), so you can leave your rootvg mirrored!

Second, if you want to run all three phases consecutively without interruption you will not be able to vary on the alternate VG without going back to a post phase 1 state, by "waking it up" (alt_rootvg_op -W) which will mount the /alt_inst filesystems.

That's because once phase 3 has finished your alternate rootvg will contain LVs/FSs with the same names as in the original VG, so you can't simply vary it on anymore.

If you plan to use "wake up" don't forget (!!) to put the VG back to sleep (alt_rootvg_op -S) before executing phase 3 or before booting from it.

But why should you mirror the alternate VG? Once you booted successfully from this alternate VG and put it into production it's your new rootvg, and you can mirror it at wish without any further considerations or worries!

wmp

I didnt understand what are you saying here..i.e. phases you are talking about. This is what I understood, you are saying that once I break the mirror and completed alt disk install on hdisk0, I will not be able to vary on that hdisk0(cloned copy)...is that right...so I will not be able to make the mirror of that on hdisk1..this is what you want to say ?

Also, I logged a call with IBM for cloning the rootvg without breaking mirrors, but they didnt recommend it as they say it would create issues.

"But why should you mirror the alternate VG >" my client wants to have the mirror copy of that alt disk install (hdisk0) also,on hdisk1, if hdisk0 fails - coz that is only the old working copy.

Virgo

In your previous comment you wrote >> I am just getting prepared for the activity ...<<

What kind of preparation is this when you don't even know anything about the phases of alt_disk copy?

I'd really advise you to get a bit more familiar with all the stuff you're trying to do, otherwise it could become very dangerous for your installation and your company!

Actually, I am aware of the process, I have done it on other systems with 2 disks in rootvg. As this system is different, I want to know that whether hdisk0 (alt disk copy) can be mirrored to hdisk1 immediately after creating alt disk install. That is the only question I have .

Thanks
virgo

Either stop after phase 1 and mirror the new VG as I wrote in my first comment, or, if you're past pase 3 wake up the cloned VG (effectively bringing it back to post phase1), mirror it, put it back to sleep (i.e. bring it back to post phase 3).

That's all I can say.

wmp

I wil check the same and revert

IBM recommended not to do the alternate disk installation with disks mirrored as they told that you may encounter  issues during installation or the process may get hung. So, I unmirrored the disk, perform the normal alt disk install and re-mirrored the disk. But I thanks for helping me in this.