Replacing Root Disks

[Vassily Gorbounov]

Dear colleagues,

I'd like to replace internal drives in my K370 and am asking you for a hints how to do it better:

1. This is a production server so it's better not to destroy it completely :)
2. Currently we have 4 2GB internal drives and would like to replace them with 2 18GB drives.
3. We have MirrorDisk/UX installed and have all lvols mirrored
4. These disks contain all system data, all application data are on external AutoRAID
5. All four internal drives are in the same vg00

As I understand (I never did the proposed procedure to the production server) I could do the following:
1. - Breake the mirror of vg00
- Make recovery tape with Ignite/UX, containing all vg00 data
- Make vgcfgbackup (or vgexport?) of two external VGs
- Remove old drives and install new one (or both new drives?)
- Boot from Ignite-created tape and recover all data (from two former disks) to the new disk
- Boot from New disk and create a mirror on the second disk
- make vgcfgrestore (or vgimport?) for external VGs

or

2. - Breake the mirror of vg00
- remove two old disks and install a new one
- prepare new disk and create a mirror of two old disks on it
- boot from new disk
- breake the mirror (remove two old remaining disks)
- remove old disks and install remaining new disk
- mirror one new disk to the other.

Could you please give me a hint of what is better, or may be both variants are bad and it's better to do smth. completely different?

Any ideas are welcomed - general opinions, notices of possible pitfalls, personal experience, links to the already discussed topics.

In general I just looking for the best solution, not for the step-by-step instructions (like how to mirror root volume - it is easily available on the forum archive).

Thank you.
Vassily

[Chris Wilshaw]

The Ignite option is by far the better one, and you can include all your volume groups in the backup, not just vg00 (although the vgexport command is an equally valid solution for the extra ones).

As far as option 2 goes, it's probably a non-starter, as your existing vg00 probably has a limit on the number of physical extents which would be too low to allow you to use the full capacity of the 18GB disks.

[Ravi_8 · Accepted solution]

Hi, Vassily

If i am in your position i would have done like this:

1.break the mirror
2.total backup of system
3.Note down the sizes of each filesystem (bdf)
4.replace the disks
5.just install the OS and create/increase the file system to the values noted in step 3
6. restore from backup
7.mirror the disk to the second

[Vassily Gorbounov]

Thank you for your advices.

As for ravi's advice - I would choose clean install but I'm afraid that it could take too long and suppose that Ignite's variant could be faster. I have around 12 hours to complete.

Thanks again