howto remove Physical Volume Group on running, non-mirrored VG

[Steve Post]

This may be a dumb question. But I have not found an answer in the forums or the website.

I have a volume group (vg1) that is NOT mirrored, and does NOT use PVG-strict mirroring.
Vg1 has 4-way striped disks, and 12 physical volumes. It has physical volume groups (let's call them PV101, PV102, and PV103). But I do not trust the listing. If I set up mc service guard with these volume groups I am worried I will not get it correct on the 2nd node in the cluster.

Now on vg00, I DO have PVG-strict mirroring and 2 physical volume groups PVG01 and PGV02. I do not want to mess with these two PVG's at all.

The question I have is: How do I get rid of PVG101, PVG102, and PVG103 in /etc/lvmpvg? I do not want to affect vg1 as it is heavily in use. I do not want to affect vg00 either (obviously).

Everything says how to add a PVG, or how to remove a PVG on a GONE volume group. That's nice. But how do you remove a PVG on a volume group IN use?? Is it possible? Is there any risk?

Vgroup Physical_volume_group
vg00 PVG01 PVG02 <--(want to leave alone).
vg1 PVG101 PVG102 PVG103 <--(want to remove PVGS w/o hurting data)

any ideas?
Steve

[James R. Ferguson]

Hi Steve:

If you merely want to eliminate the physical volume group definitions from /etc/lvmtab so that it appears as if you never used this feature, then you can simply edit /etc/lvmtab and remove them.

Regards!

...JRF...

[Steve Post]

No unmounting of file systems?
No stopping of databases?
Ok. But I'll still wait to do this task next time I can reboot. (I'm paid to be paranoid).

I noticed that when I run lvdisplay -v on all of the logical volumes, the only one that appear to use pvg-strict mirroring is vg00.

Thanks. Points are coming.
steve

[Steve Post]

No wait. You meant ascii file /etc/lvmpvg, data file /etc/lvmtab. Right?

[Pete Randall]

James,

I'm confused!! This morning, in http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x4c1deea29889d611abdb0090277a778c,00.html you said:


The /etc/lvmtab is a binary data file. As noted, 'strings
/etc/lvmtab' will expose the printable characters. The file is not
and should not be editted manually in any fashion.


I surely don't mean to pick on you but I'm even more confused that usual.

Pete

[Pete Randall]

Ahh, /etc/lvmpvg - that would explain it - and make more sense, too.

Pete

[James R. Ferguson · Accepted solution]

Hi (again):

Yes, I meant 'etc/lvmpvg' !!!

This really must not be my day...

Regards!

...JRF...

[Steve Post]

Ok. THANKS. Both of you. James, I thought that was what you meant.
Steve

[James R. Ferguson]

Hi (again) Steve:

Interestingly, there is a reference in the Technical Knowledge Base to MC/ServiceGuard and '/etc/lvmpvg', document #UXSGLVKBRC00001710.

Essentially the document notes that unless you carefully adjust/update device file paths to correctly match each node in the cluster, you are better off eliminating the '/etc/lvmpvg' file from all but one node and simply confine your LVM maintenance to that node.

Clearly, you are on the right track.

Regards!

...JRF...

[George Abraham_1]

hai

You can edit the /etc/lvmpvg file..
Since these PVs are not in use now dont bother to unmount the filesystems

cheero!

george

[Steve Post]

James,
Ah you got me. I read that too. I have actually 4 device names for each disk on the two nodes. And every one of them looks different from one node to the other.
The PVG looks like (in THIS case), a fancy way for me to screw up the computer.

George,
The file systems ARE in use. I'll play it safe and do this work on my next scheduled down-day.
STeve

[George Abraham_1]

hai

Always better to play safe especially when dealing with LVM... good luck..

cheers
George