topic Re: How to import volume group and it's logical volumes in Operating System - HP-UX

How to import volume group and it's logical volumes

Lars Bylander — Tue, 19 Aug 2008 11:20:50 GMT

My L2000 (rp5450) server have 4 disks, 2 disks used for vg00 and 2 disks vg01. Due to failure in one of the disks used by vg00 I have repleaced the vg00 disks and reinstalled using ignit-ux. User data is located on the vg01 disks. I would appreciate some guidance how to import the vg01 disks si they can be used by the newly installed OS (version 11i). I do not have any LVM configuration backup.

Best regards,
Lars Bylander

Re: How to import volume group and it's logical volumes

Pete Randall — Tue, 19 Aug 2008 11:28:39 GMT

vgimport vg01 /dev/dsk/cUtVdW /dev/dsk/cXtYdZ

Assuming your logical volumes used conventional names (lvol1, lvol2, etc), there is no need for a map file.

Pete

Re: How to import volume group and it's logical volumes

SKR_1 — Tue, 19 Aug 2008 11:36:43 GMT

If you know the disk which were there in vg01, then you can directly import the Volume Group.

mkdir /dev/vg01
mknod /dev/vg01/group c 64 0x------
vgcreate
vgimport /dev/vg01 disk name

Thanks

SKR

Re: How to import volume group and it's logical volumes

Lars Bylander — Wed, 20 Aug 2008 09:51:17 GMT

Thank you for your comments.

Will vgimport write anything to the disks to be imported? or is only /etc/lvmtab and eventually /etc/lvmconfig updated?

Executing vgimport with the option preview:
vgimport -m /tmp/vg01.mapfile -p -v /dev/vg01 /dev/dsk/c2t0d0 /dev/dsk/c1t0d0
Beginning the import process on Volume Group "/dev/vg01".
Logical volume "/dev/vg01/lvol20" has been successfully created
with lv number 1.
Logical volume "/dev/vg01/lvol21" has been successfully created
with lv number 1.
Volume group "/dev/vg01" has been successfully created.

The map files used where a copy of the mapfile: /etc/lvmconf/vg01.mapfile
Strange that lv number 1 points to 2 logical volumes!!

Best regards.
Lars

Re: How to import volume group and it's logical volumes

Torsten. — Wed, 20 Aug 2008 11:08:23 GMT

What is the contents of your mapfile?

Re: How to import volume group and it's logical volumes

Lars Bylander — Wed, 20 Aug 2008 11:52:35 GMT

The contents of the map file is:
# cat /tmp/vg01.mapfile
1 lvol20
1 lvol21

/Lars

Re: How to import volume group and it's logical volumes

Torsten. — Wed, 20 Aug 2008 11:59:31 GMT

This is the problem - should be like this:

# cat /tmp/vg01.mapfile
1 lvol20
2 lvol21

IMHO you don't need a mapfile for your config, unless the lvols should be not named lvol1 and lvol2.

Re: How to import volume group and it's logical volumes

James R. Ferguson — Wed, 20 Aug 2008 12:18:21 GMT

Hi Lars:

As Torsten notes, the mapfile is useful when your logical volume names are *not* standard (i.e. are not 'lvol1', 'lvol2', etc. associated with logical volume #1 and #2, respectively).

However, there is another use of the mapfile, and that is to contain the Volume Group ID (VGID) of the physical disks comprising the volume group. If this is included (by specifying '-s' during 'vgexport' *and* during the subsequent 'vgimport'), then you can avoid having to specify the device files (pv_paths) during the process. The VGID disk signiture is read instead and and all physical disks with a matching VGID collected into a volume group.

This is particularly useful during cold-installations or when disk are moved among servers, or when SANs are rezoned, since one doesn't have to look up pv_paths for the affected disks.

See the manpages for 'vgexport' and 'vgimport' for more information.

Regards!

...JRF...

Re: How to import volume group and it's logical volumes

Lars Bylander — Wed, 20 Aug 2008 12:30:07 GMT

Hi James,

Well I had a disk crash and did not have anything saved from vgexport. Some earlier LVM setup seems to have generated the strange mapfile:

# cat /etc/lvmconf/vg01.mapfile
1 lvol20
1 lvol21

After executing vgimport with preview I think that lvol20 and lvol21 are treated as the same logical volumes.

Anyway, since I do not want risk that data on the vg01 disks are destroyed, does vgimport only write to the config files in /etc?

Re: How to import volume group and it's logical volumes

Torsten. — Wed, 20 Aug 2008 12:38:28 GMT

If you are not sure about the mapfile - leave it away and try without.

vgimport -p ...

will preview the results.

Re: How to import volume group and it's logical volumes

Lars Bylander — Fri, 22 Aug 2008 09:14:58 GMT

The problem is solved. Executing vgimport without any mapfile created vg01/lvol1.
After executing fsck -F vxfs -o full /dev/vg01/lvol1 it was possible to mount the logical volume in read/write mode. Before running fsck it was only possible to mount in read only mode.

Thank you everyone, Lars

Re: How to import volume group and it's logical volumes

OldSchool — Fri, 22 Aug 2008 14:51:07 GMT

Lars:"Due to failure in one of the disks used by vg00 I have replaced the vg00 disks and reinstalled using ignit-ux."

Uh...glad you got it resolved, but it seems you have no mirroring? The L2000 "internal" disks are hot-swappable, and you *shouldn't* have needed to Ignite the box...shouldn't have had any downtime at all.

If not already installed, consider licensing / installing MirrorDisk.

Re: How to import volume group and it's logical volumes

Lars Bylander — Mon, 25 Aug 2008 05:28:30 GMT

Hello Oldschool,

You got a point and I will check the license cost.

Thanks, Lars