topic Re: Importing LUNs in Operating System - HP-UX

Importing LUNs

Sid Bytheway — Sat, 19 May 2001 17:07:54 GMT

After a fresh install, I am ready to import volumes I exported prior to the reinstall. In SAM I see I have two controllers and a LUN. I select the LUN, and it wants me to either put it in a new volume group, or an old one, vg00. I want it to go in the one it was in before. We had 3, vg02, vg03, and sybase. Can I tell it to configure itself the way it was before?

Re: Importing LUNs

Sid Bytheway — Sat, 19 May 2001 17:10:02 GMT

I don't know how this got in the database section, I thought I was in the 'general' area.

Re: Importing LUNs

Byron Myers — Sat, 19 May 2001 17:18:29 GMT

You should be able to configure the way it was before. What vgexport command did you use? (like vgexport -m /tmp/mapfile vg02)

Re: Importing LUNs

Sid Bytheway — Sat, 19 May 2001 17:20:27 GMT

No options, simply

vgexport vg03

after doing

vgchange -a no vg03

etc.

I did save a copy of the output of vgdisplay

Re: Importing LUNs

Sid Bytheway — Sat, 19 May 2001 17:31:55 GMT

I get the lvmtab and other files off backup if need be.

Re: Importing LUNs

Byron Myers — Sat, 19 May 2001 17:36:25 GMT

If you can tell which disks belong in a corresponding vg, then this is a way to do it.
for example, vg02 - if c1t0d0 c2t0d0 were the disk on the old system (your saved vgdisplay -v vg02 would show this - if you used the "-v" option), and on the new OS, the disks are, say c5t0do and c6t0d0, then:
1. create the directory /dev/vg02
2. create the "group" file in /dev/vg02.
The minor number MUST be unique.
do a "# ls -al /dev/vg* | grep group" to
see the existing group minor numbers.
Example:
# ls -al /dev/vg*
the minor numers shown might be:
0x000000 (root volume group vg00)
0x010000 (some other volume group)
Pick the next minor number (in hex), in
this example it is 0x020000.
#mknod /dev/vg02/group c 64 0x020000

then
# vgimport /dev/vg02 /dev/dsk/c5t0d0 /dev/dsk/c6t0d0
(this is using the new disks)

then
# vgchange -a y vg02
# vgdisplay -v vg02
you should see the logical volumes - lvol1, lvol2, etc.
You will need to figure out which of these logical volumes belongs where. If you saved a copy of /etc/fstab, this will help.

The usual method to export vg's for OS re-installs is to use "vgexport -m -s " this prevents all of this lv stuff.

Re: Importing LUNs

Sid Bytheway — Sat, 19 May 2001 20:26:18 GMT

Thank you. This is all very useful. But it sounds like I have no guarantee that the disk names will be the same on the new OS?

I did no do vgdisplay -v
only vgdisplay.

I am trying to retrieve a copy of lvmtab, but if the disks are named differently it will complicate the whole process. It sounds like I better just recreate the volumes and restore from backup.