Rename volume group?

[Sean OB_1]

Is it possible to rename a volume group, and if so what are the ramifications?

[Robert-Jan Goossens · Accepted solution]

Hi,

Filesystem: Rename volume groups and logical volumes
date: 4/24/97
document description: Filesystem: Rename volume groups and logical volumes
document id: A4158692

You may provide feedback on this document

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Problem Description

Can you explain how to rename a volume group (VG) and the logical volumes
within that VG?

Configuration Info

Operating System - HP-UX
Version -10.01
Hardware System -877

Solution

Follow these guidelines for non-root volume groups:

1. umount /filesys (for each mounted filesys)

2. vgchange -a n /dev/vgname

3. vgexport -m mapfile /dev/vgname

4. vi mapfile (to set up new logical volume names)

5. mkdir /dev/vgnewname

6. mknod /dev/vgnewname/group c 64 0x

7. vgimport -m mapfile /dev/vgnewname /dev/dsk/cxtyd0

where x and y are the device files for the physical volumes in
the VG.

Hope it helps,

Robert-Jan.

[Rita C Workman]

No I don't believe you can not 'rename' a volume group...

You can do a vgexport and a new mknod to change the minor # (0x_ _ 0000), and then vgimport it back.
But to change the name /dev/vgname .. nope ..

What you might do is...do a complete backup of the affected data. Create a new vg and restore the data to the new location.

Just my thoughts,
Rita

[Uday_S_Ankolekar]

Command vgimport can be used to rename a volume group. Specify the new name in the 'vgimport' command -- it doesn't matter what the old name was.
for Eg:
mkdir /dev/vgnewname
mknod /dev/vgnewname c 64 0x06000
vgimport -v -s -m vgoldname dev/vg05

-USA..

[Uday_S_Ankolekar]

....contd..
vgimport -v -s -m vgoldname dev/vgnewname

[Sean OB_1]

Thanks for the responses. How long does this process take? Is it variable depending on the vg size, or is it just recreating the vg tables on the disk?

[Pete Randall]

Sean,

I believe, assuming I recall correctly, that the import process is relatively quick - measured in seconds rather than minutes, even.

Pete

[A. Clay Stephenson]

The vgimport process is essentailly instantaneous. The typical reason for doing this is for database raw devices. You can always use symbolic links to accomplish the same thing.

[Sean OB_1]

Thanks for the answers everyone. I'm not sure I'll need to do this, but if I do then you've been a big help.

I'll award points accordingly when I do this work.

[Tim D Fulford]

I would not even attempt to do this it is puerely esotric....

1 - The convention is to name root volume group vg00
2 - It is imperitive that /dev/vg00/lvol1, 2 & 3 are in the right order on the disk for boot purposes. Calling them by other names confuses the issue.
3 - Assume you have renamed vg00 then certain scripts start to fail. You will have to fix these scripts which is another task you probably could do without.

However I DO name non-standard logical volumes in vg00. e.g. I would not create /dev/vg00/lvol9 it would be /dev/vg00/app1 etc.

Regards

Tim

[Sridhar Bhaskarla]

Hi Sean,

As told by others, renaming a volume group means exporting and importing it back. The time it takes to export is instantaneous. But the time it takes to import depends on the option you use (like -s or -f etc) and the number of PVs in the volume group. One of my systems have 100+ PVs in one volume group and it took me around 10 mins to import using -s option. I suggest using -f option. Look at vgexport and vgimport man pages.

But renaming logical volumes is very simple. Just rename lvolx and rlvolx to your_lv_name and ryour_lv_name. This is applicable to even logical volumes in vg00 also. But you have to be very careful while renaming and be sure to update your fstab. For ex., if I want to rename lvol5 to var, I would do the following.

#mv /dev/vg00/lvol5 /dev/vg00/var
#mv /dev/vg00/rlvol5 /dev/vg00/rvar

vi /etc/fstab and change the reference to /dev/vg00/var.

-Sri

[Sean OB_1]

Just some more information on this.

Here is what I have now.

/dev/development/.... with 5 lvols
I need to move this volume group to new disks, so I've created a new volumegroup:

/dev/newdev/... with the 5 lvols.

I plan on copying the data to the new vg on temp mountpoints, then once everything is verified to be there, removing the /dev/development volume group and renaming /dev/newdev to /dev/development.

Does anyone see any issues with doing this as outlined by the responses above?

[Sridhar Bhaskarla]

Hi,

Your way will work and that's the safest way.

Keep your old volume group intact for couple of days and delete it once the new setup is found stable.

-Sri