topic vgcfgbackup in Operating System - HP-UX

vgcfgbackup

Tammy Liang — Wed, 05 Nov 2003 16:06:26 GMT

I got following message when I run vgcfgbackup:
vgcfgbackup: /etc/lvmtab is out of date with the running kernel:Kernel indicates 5 disks for "/dev/vg01"; /etc/lvmtab has 4 disks.
Cannot proceed with backup.

I checked /etc/lvmtab shows there are 4 disks
which is correct. How can I change kernel to
recognize there are only 4 disks instead of 5?

Thanks for any help

Re: vgcfgbackup

Helen French — Wed, 05 Nov 2003 16:15:51 GMT

A good explanation and solution can be found from this document TKB# KBRC00000632:

http://www1.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000065011231

Re: vgcfgbackup

Tammy Liang — Wed, 05 Nov 2003 16:45:33 GMT

Thank you for the doc. I checked it, but it
does not apply to my situation. I don't have
missing disk device. The number of disk are correct in /etc/lvmtab and /etc/lvmconf/vg01.conf files (4 disks). It also correct after run "vgcfgrestore -n /dev/vg01 -l" command. vgdisplay do indeed shows Cur PV is 5, and Act PV is 4. I need to fix it, so Cur PV also shows 4 instead of 5. I have too many disks instead of missing disks.

Thank you....

Re: vgcfgbackup

Helen French — Wed, 05 Nov 2003 16:52:29 GMT

I would try the following:

1) Check and apply all latest LVM and Kernel patches.

2) Reactivate VG (vgchange -a n and vgchange -a y)

Re: vgcfgbackup

Marco Santerre — Wed, 05 Nov 2003 16:57:56 GMT

I did have something similar to that that occured to me not too long ago, and it had to do with the fact that I had BCV synchronized with my standard devices and that I added a disk in my Volume Group on my standard and the split. Then my BCV Volume groups would show a discrepency between my Act PV and my Cur PV. Would you happen to have done something similar to that?

Re: vgcfgbackup

Ashwani Kashyap — Wed, 05 Nov 2003 17:03:57 GMT

Make a copy of the lvmtab file first .
THen run vgscan ( man vgscan ) in preview mode to see if you get the correct number of PV in the volume groups .

if you are satisfied with that , then re run vgscan without the preview option , whcih will recreate your lvmtab file . Then run vgcfgbackup again .

If it doesnot run , you can always restore your copied lvmtba file .

Re: vgcfgbackup

Dietmar Konermann — Wed, 05 Nov 2003 17:24:52 GMT

Tammy,

actually your VG physically consists of 5 disks, believe me. The 5th (maybe phantom) disk can usually be vgreduce'ed out of the VG using:

vgreduce -f /dev/vg01

However, if LVM believes to have extents on that PV then this command would not work, but at least you get more precise information about the actual problem.

So please run the command above and post the results.

Best regards...
Dietmar.

Re: vgcfgbackup

Rajeev Shukla — Wed, 05 Nov 2003 17:45:25 GMT

I had the same problems few days back, what happens is that by some reasons the VGRA gets corrupted in all the disks, and if you have tools to look at those areas on the disk you'll find that it has an counter saying the number of disks involved in this VG is 5 but thats not the case if you look at you'r lvmtab.
I tried vgexport and vgimport but trust me nothing will work.
The only solution to decrement the counter on the disk is to do a
vgreduce -f /dev/vg01
after doing this you'll find Current PV and Active PV same.

Re: vgcfgbackup

Timothy P. Jackson — Wed, 05 Nov 2003 21:09:16 GMT

Hi Tammy,

I have seen this quite a bit in cases where a hard drive will crash and a replacement is put back into the VG incorrectly. It thinks that there are five but you really only have four. I have used Dietmar's proceedure and then followed it up by doing a vgscan to create a new lvmtab. besure to make a copy of the original lvmtab first

Re: vgcfgbackup

Tammy Liang — Thu, 06 Nov 2003 09:08:25 GMT

Can I run "vgreduce -f /dev/vg01" on a running production system?

Re: vgcfgbackup

Dietmar Konermann — Thu, 06 Nov 2003 09:12:57 GMT

Yes.

Re: vgcfgbackup

Tammy Liang — Thu, 06 Nov 2003 13:40:13 GMT

Hi Dietmar:
Can this system be rebooted before I have chance to run "vgreduce -f /dev/vg01"?

Re: vgcfgbackup

Dietmar Konermann — Fri, 07 Nov 2003 02:51:12 GMT

Should be no problem... after activating again vg01 should show the same problem, unless you run the vgreduce -f.

But I'm wondeirng why you want to reboot before resolving the problem.

Best regards...
Dietmar.

Re: vgcfgbackup

Tammy Liang — Fri, 07 Nov 2003 09:45:15 GMT

Thank you for the reply.
I was afread user reboot the system before I have chance to run vgreduce command. My concern is the system won't start up due to
VGRA may not have correct information.
I got chance to login the system which is at different country and get it fixed..

Thanks again for the help...