topic Re: More volume group problems in Operating System - HP-UX

Re: More volume group problems

Melissa Murphy — Mon, 11 Jun 2001 17:50:20 GMT

Another question ...

I'm still pretty stuck and see this error:
# vpdisplay -v /dev/dsk/c4t0d1
pvdisplay: Couldn't find the volume group to which
physical volume "/dev/dsk/c4t0d1" belongs.
pvdisplay: Cannot display physical volume "/dev/dsk/c4t0d1".

What does it mean that it "belongs"?

Thanks,
Melissa

Re: More volume group problems

James R. Ferguson — Mon, 11 Jun 2001 18:04:09 GMT

Hi Melissa:

OK. This is a follow-on to today's earlier post. As I indicated there, if you look do:

# strings /etc/lvmtab

...then you will see the volume groups and associated device files. /etc/lvmtab is that which is rebuilt when you did the 'vgscan'.

It's not totally clear what you are attempting to do, nor in total, what you have done.

First, do you have data on your /dev/vgraid volume group that you care about either on this system or another?

...JRF...

Re: More volume group problems

Melissa Murphy — Mon, 11 Jun 2001 18:16:08 GMT

Mr. Ferguson,

No, there is no data on the vgraid volume group (if it's still there ...) These are pretty clean systems with nothing of importance on them.

Well, I tried to get rid of the volume group, actually. I was going to redo it mounted to another place, since I wasn't sure how to remount it to somewhere else. I think what happened is I didn't delete the logical volume first and now I'm a little hosed. I can't remove the physical volume, because a volume group is associated with this. Again, I'm not sure where this is. I tried to go through the steps we discussed in the previous thread, but I still can't create a new volume group. I have a /dev/vgraid and a /dev/vgraid/group with 0x010000, but when I try vgcreate /dev/vgraid /dev/dsk/c4t0d1, I get that the path does not specify a valid physical volume. So how do you think I messed up my physical volume?

Sorry to be a pain - I know I don't know that much here, but I'd really like to get this figured out. :)

Thanks,
Melissa

Re: More volume group problems

James R. Ferguson — Mon, 11 Jun 2001 18:55:20 GMT

Hi Melissa:

Please, you are not being a "pain". We're here because we *want* to be here!

First, your 'vgdisplay' syntax is wrong. In your case, try:

# vgdisplay -v /dev/vgraid

...JRF...

Re: More volume group problems

Joel Shank — Mon, 11 Jun 2001 18:58:39 GMT

Hi Melissa

I don't think your vgexport worked properly if you still have /dev/vgraid and /dev/vgraid/group. vgexport deletes these. I'd try doing a vgexport /dev/vgraid -v to see if that will clear everything out.

If this works, then all you have to do is recreate the volume group:
1) mkdir /dev/vgraid
2) mknod /dev/vgraid/group -c 64 0x010000
3) pvcreate -f /dev/rdsk/c?t?d?
4) vgcreate ...

If the vgexport doesn't work, we'll have to look at the messages it produces to see if we can figure it out.

-OR-

You can try to force the pvcreate and try to recreate the volume group from where you are now. Try:
pvcreate -f /dev/rdsk/c?t?d?

Then your vgcreate.

Good Luck -- jls

Re: More volume group problems

Melissa Murphy — Mon, 11 Jun 2001 19:18:33 GMT

Ahh, of course. :)

Alright, here's the output of the vgdisplay:

# vgdisplay -v /dev/vgraid
vgdisplay: Volume group "/dev/vgraid" does not exist in the "/etc/lvmtab" file.
vgdisplay: Cannot display volume group "/dev/vgraid".

And that of vgexport:

# vgexport -v /dev/vgraid
Beginning the export process on Volume Group "/dev/vgraid".
vgexport: Volume group "/dev/vgraid" does not exist in the "/etc/lvmtab" file.
vgexport: Couldn't export volume group "/dev/vgraid".

I was pretty sure I did a vgexport early on and it was okay ... but maybe now I'm not so sure.

So, whatdya think?

Thanks,
Melissa

Re: More volume group problems

Joel Shank — Mon, 11 Jun 2001 19:23:14 GMT

Melissa

I think you should force the pvcreate (use the -f option), but be sure you specify the correct physical volume.

After the device is pvcreated, you should be able to do a vgcreate using it.

Let us know how this works -- jls

Re: More volume group problems

Melissa Murphy — Mon, 11 Jun 2001 19:25:02 GMT

Ahhh, wait a second! I did the pvcreate -f and that worked out. Then I created my vgraid and my logical volume and everything looks all right!

Wonderful! Thanks a bunch! :)
You'll hear from me soon -- the next time I go poking around. :)

Later,
Melissa

Re: More volume group problems

James R. Ferguson — Mon, 11 Jun 2001 19:35:57 GMT

Hi Melissa:

So, if you want to build a volume group from scratch, using one physical disk, /dev/dsk/c4t0d1 and you want the volume group called /dev/vgraid then:

# pvcreate -f /dev/dsk/c4t0d1
# mkdir /dev/vgraid
# mknod /dev/vgraid/group c 64 0xNN0000 # where NN is the unique minor number (in hex)
# vgcreate /dev/vgraid /dev/dsk/c4t0d1
# lvcreate -L -n lvol1 /dev/vgraid

Remember to choose a unique minor number for 'mknod' by looking at what is already used with:

# ls -l /dev/*/group

Take a look at the man pages for each command and/or the HP-UX System Administration Tasks manual I cited in our earlier dialog for more details.

Regards!

...JRF...

Re: More volume group problems

Bill McNAMARA_1 — Tue, 12 Jun 2001 08:41:32 GMT

Should have mentioned that earlier..

A vgexport leave the disk header on the disk that identify the disk is an lvm managed.

The long shot of this:
To reuse a disk already used by lvm, you must pvcreate -f /dev/rdsk/c?t?d?

Stick around with the forums anyway, you'll have fun!

Later,
Bill