topic Re: vgchgid command in Operating System - HP-UX

vgchgid command

John Jimenez — Wed, 01 Aug 2007 15:56:13 GMT

I have an RP7420 on a EMC CLARiiON. I am trying to utilize snap clone on a 200 gig Volume group that is on two 100 gig LUNS. The tricky part is that I am doing the snap clone from and to the same host

Here is my procedure so far, that is not working. I am trying to snap clone source vg02 to vg20.

1) I unmount and deactivate vg20
2) I snap clone vg02 to vg20 (took about 4.5 hours, which seems like a long time). LUN 0 (raidgroup3) to LUN 200 (raidgroup5). LUN 1 (raidgroup4) to LUN 201 (raidgroup6).
3) I tried to vgchgid but it will not take. It was mentioned that I need to vgexport, but I do not see any mention of this on the man pages. Also, if I do need to vgexport, does anyone know what options I need to use?

Any input is greatly appreciated.

Re: vgchgid command

skt_skt — Wed, 01 Aug 2007 22:53:37 GMT

could u mention the exact command?Looks like your commands picks the source disks too which is part of the vg02 now

Re: vgchgid command

Kevin Wright — Thu, 02 Aug 2007 01:08:07 GMT

yes, vgexport. No specific options required.

Re: vgchgid command

John Jimenez — Thu, 02 Aug 2007 09:55:13 GMT

Santhosh,
Here is the message I get when I vgchgid one of the disks with vg20 unmounted and deactivated, without vgexporting it. what is funny is that when I do the other LUN I just get the prompt back. Does it look like it worked for one and not the other?

=> #vgchgid /dev/rdsk/c43t9d4
vgchgid: disk "/dev/rdsk/c43t9d4" is already in vg "/dev/vg20".
RP7410:root /
=> #vgchgid /dev/rdsk/c44t9d3
RP7410:root /

Re: vgchgid command

John Jimenez — Thu, 02 Aug 2007 09:57:18 GMT

Kevin,
The only time I use vgexport in the past, is to get rid of volume groups. But in this case won't I need to gvimport it after the vgchgid? If I use no optiond isn't it gone?

Re: vgchgid command

skt_skt — Thu, 02 Aug 2007 10:02:13 GMT

vgexport vg20
vgchgid disklist
vgimport vg20

Re: vgchgid command

John Jimenez — Thu, 02 Aug 2007 10:15:55 GMT

Something funky going on here. It thinks that they are in seperate volume groups when they are not. something must be corrupted in one of them. I typoed at the beginning. I am using LUN 203 and LUN 204 for the clone. I just double checked and we are using LUN 203 c44t9d3 and LUN 204 C43t9d4. but this is what I get after vgexporting it. Maybe I should start all over with new LUN numbers and a different volume group besides vg20?

=> #vgchgid /dev/rdsk/c44t9d3 /dev/rdsk/c43t9d4
vgchgid: physical volume "/dev/rdsk/c44t9d3" and "/dev/rdsk/c43t9d4" do not belong to the same volume group.

Re: vgchgid command

Mridul Shrivastava — Thu, 02 Aug 2007 18:26:59 GMT

When u executed vgchgid on #vgchgid /dev/rdsk/c44t9d3 it was successful , hence the ID got changed, however on the other disk it failed..

So now it is behacing the way it should since both the disk contain different vgid hence system see them as part of two difference VGs.

Re: vgchgid command

John Jimenez — Thu, 02 Aug 2007 18:37:10 GMT

So the command always has to be done at the exact same time. But even if I include both raw disks in the same command, is'nt there a chance that it will be off by a second and mess it up. In the meantime, I have removed the LUN alltogether, rebooted the server, and starting the procedure over. I will let you know how it goes this time when it is done.

Re: vgchgid command

skt_skt — Thu, 02 Aug 2007 20:31:47 GMT

make sure to execute the vgchgid in a single shot for all the disk from vg20.there should not be any issue if your LUN list(source & dest) is perfect

Re: vgchgid command

A. Clay Stephenson — Thu, 02 Aug 2007 21:12:32 GMT

>>> So the command always has to be done at the exact same time. But even if I include both raw disks in the same command, is'nt there a chance that it will be off by a second and mess it up. In the meantime, I have removed the LUN alltogether, rebooted the server, and starting the procedure over. I will let you know how it goes this time when it is done.

It would, of course, be all but impossible to actually write the data to multiple disks at the same time but that is not necessary. What is necessary is that all the PV's that are to form a volume group be included in the same vgchgid command. Vgchgid generates a new unique VGID each time it is run so if you run the command separately for each PV then each will get a different VGID and vgimport will tell you that "that dog won't hunt" --- or a similar error message,

Re: vgchgid command

tkc — Thu, 09 Aug 2007 11:26:17 GMT

i was wondering if you will need to run vgcfgbackup after snap cloning the vg02 to vg20. this will make sure your vg20 which has been changed after the snap clone its configuration is being updated in the system.