Dyanmic Root Disk(DRD) as an alternate disk

[Abhzi]

Hello All,

I have BL860c i2 on which root disk is hardware mirrored. I wanted to keep alternate boot disk with me in case of emergency, so I have used DRD to clone the system.

Can I use this as an alternate boot disk? I dont want to activate it because if I will do it will become primary boot disk at next reboot. All I want is a safe copy of root with me(by doing drd sync every weekend) which I can use in case of emergency. Please advise if this is feasible and how can I achieve this?

[Torsten.]

Why not?

The BL860c i2 has 2 internal disks, hardware mirrored in your case.

So you need to use an external disk (in SAN) as a destination disk for DRD.

If you activate the clone, the system simply swap the boot entries, this make the clone the primary boot disk. YOu can select this disk also during boot manually (make sure a boot entry exists in boot menu).

[Abhzi]

Yes Right!

But what will happen  in scenario where I haven't activated the DRD and the server is down. Can in that case I can boot the server from DRD disk?

[Torsten.]

Yes, of course.

As said, activate just swp the boot entries, so your server AUTOMATICALLY boots from the clone.

You can ALWAYS boot the alternate path (the clone) manually without doing an activate.

But if your disk is on SAN, an existing boot entry will help you much, because you need to search and find your LUN otherwise.

[Abhzi]

Thanks Torsten. It is pretty much clear now.

By making boot entry of LUN, do you mean setting up as " setboot -a ".

And if I am not wrong, in the manual boot from DRD disk(instead of activating it) system will come up on /dev/drd00?

[Abhzi]

I think I am wrong, as it has copied fstab, it will come up on vg00 only.

[Torsten. · Accepted solution]

>> And if I am not wrong, in the manual boot from DRD disk(instead of activating it) system will come up on /dev/drd00?

NO.

AFAIR the VG is drd00 as long as you mount the clone to the running system.

But it is a clone, hence it is VG00 too.


You don't need any alternate boot path to your hardware RAID, so you can set the alternate or HA alternate to the clone.


Consider to disable autosearch to prevent an automatic boot from the clone in case the original system has a problem.

[Abhzi]

Thanks alot!! 

I'll keep autosearch off as there is no alternate boot device(since the root is hardware mirrored). But will add my DRD disk in boot menu so that I can boot from it whenever we need to.