topic Re: VG Question in Operating System - HP-UX

VG Question

Diadina Cotte — Tue, 18 Jun 2002 15:46:36 GMT

Hi
I was trying to create a new physical c0t0d2 and logical volume and I got this error msg.

#pvcreate /dev/rdsk/c0t0d2
pvcreate: The physical volume already belongs to volume group.

How do I check what vg's are mounted on c0t0d2?

thanks!

Re: VG Question

Jeff Schussele — Tue, 18 Jun 2002 15:52:10 GMT

Hi Diadina,

Try
pvdisplay -v /dev/dsk/c0t0d2

Also check the
/etc/lvmtab
file to see if it's allocated to any VGs on *this* system.

Note: On shared arrays this drive may be in a VG on ANOTHER system. So you need to check *all* systems connected to the array.

If there are actually NO systems currently using it - use
pvcreate -f /dev/rdsk/c0t0d2
To force the initialization.

HTH,
Jeff

Re: VG Question

harry d brown jr — Tue, 18 Jun 2002 15:52:23 GMT

pvdisplay -v /dev/dsk/c0t0d2 | more

Note the use of the block device "dsk" and not "rdsk".

live free or die
harry

Re: VG Question

MANOJ SRIVASTAVA — Tue, 18 Jun 2002 15:52:38 GMT

Hi Diadina Cotte

Do a strings on /etc/lvmtab | more to know where does this disk belong to .Inc ase you are sure that this disk is a new disk ( ioscan and diskinfo) and doesnt belong to any vg then you can just rename lvmtab to lvmtab.old and recreate the lvmtabb using vgscan -a . The again do a strigns on the lvmtab.

In case you dont find it there then just do a pvcreate -f /dev/rdsk/c0t0d2 ( force option)
vgcreate /dev/vgxx /dev/dsk/c0t0d2

and you are good to get going.

All the best.

Manoj Srivastava

Re: VG Question

Patrick Wallek — Tue, 18 Jun 2002 15:52:59 GMT

You can see if c0t0d2 belongs to a VG by doing a

# strings /etc/lvmtab | grep c0t0d2

If you get results, then that disk already belongs to a VG. Too see all VGs and their disks do a

# strings /etc/lvmtab > /tmp/lvmtab.temp

# cat /tmp/lvmtab.temp

If c0t0d2 does not belong to any VGs, just put the '-f' option on your pvcreate command.

# pvcreate -f /dev/dsk/c0t0d2

This will force the pvcreate on that device.

You will get that error if that device was EVER a part of a VG.

Re: VG Question

S.K. Chan — Tue, 18 Jun 2002 15:53:11 GMT

To find out if c0t0d2 is configured in any of your existing VGs you can do ..
# strings /etc/lvmtab
OR
# vgdisplay -v |grep dsk
If you don't see c0t0d2 in the above 2 cases it's more likely that the disk was previously used in a VG. To reuse it do ..
# pvcreate -f /dev/rdsk/c0t0d2
Be very sure before you run pvcreate with -f option.

Re: VG Question

Dave Chamberlin — Tue, 18 Jun 2002 15:55:02 GMT

Hi,
Use SAM. Choose "Disks and File systems", then "Disk Devices". This will take several seconds, but will list each disk in your system and show which volume group each is in, as well as other useful info.

Re: VG Question

PIYUSH D. PATEL — Tue, 18 Jun 2002 15:55:03 GMT

Hi,

pvdisplay -v /dev/dsk/c0t0d2 |more

Check in the /etc/lvmtab file also whether the disk is present or not.
#strings /etc/lvmtab

If it is not present then you can forcefully create the vg by using.

pvcreate -f /dev/rdsk/c0t0d2

Piyush

Re: VG Question

Bill McNAMARA_1 — Tue, 18 Jun 2002 15:55:44 GMT

recall too that you can have a disk in use that is not managed by lvm..

Check your /etc/fstab for all filesystem locations/ logical configurations.

As mentioned pvcreate -f will blowaway the disk LVM headers..
make sure you're selecting the right disk by blinking it's leds:

dd if=/dev/dsk/c0t0d2 of=/dev/null

Later,
Bill

Re: VG Question

James R. Ferguson — Tue, 18 Jun 2002 15:57:13 GMT

Hi:

There is a LVM header on the disk you are attempting to 'pvcreate'.

You can attempt to match the device to one present in /etc/lvmtab.

Do 'strings /etc/lvmtab'. If your disk does *not* appear there, then either you have attached a disk from another system or you have 'lvreduce'ed filesystems that were on the disk (as it belonged to a volume group) and 'vgreduce'd the disk (as it belonged to a volume group.

If you are truly sure that you want to 'pvcreate' this disk, do:

# pvcreate -f /dev/rdsk/cXtYdZ

Regards!

...JRF...

Re: VG Question

Diadina Cotte — Tue, 18 Jun 2002 16:22:41 GMT

Hi I did a more on the lvmtab:
root@apache:/etc#>more lvmtab
^CM-h^E/dev/vg00
wM-f;U1M-WyB^A/dev/dsk/c0t4d0
/dev/vg03
wM-f;U5*M-[u^A/dev/dsk/c0t0d0
/dev/vg04
wM-f;U5*M-\M-!^A/dev/dsk/c2t1d1
/dev/vg05
wM-f;U56-^Q^A/dev/dsk/c0t8d0
/dev/vg06
wM-f;U56-W^A/dev/dsk/c0t9d0

then enforce the pvcreate
using dsk

root@apache:/dev#>pvcreate -f /dev/dsk/c0t0d2
pvcreate: "/dev/dsk/c0t0d2": not a character device.
root@apache:/dev#>

enforce the pvcreate
using rdsk

root@apache:/dev#>pvcreate -f /dev/rdsk.c0t0d2
Couldn't stat physical volume "/dev/rdsk.c0t0d2":
pvcreate: Couldn't open physical volume "/dev/rdsk.c0t0d2":
No such file or directory
root@apache:/dev#>

....but I got this msg. Whats the difference between /dsk and /rdsk ??

Re: VG Question

S.K. Chan — Tue, 18 Jun 2002 16:28:54 GMT

The pvcreate command expect "character" device file to be used (ie rdsk) or "raw" whereas other commands like pvdisplay can use "block" device file (dsk).
It should be run like so ..

# pvcreate -f /dev/rdsk/c0t0d2

You got a typo in your last "pvcreate" command.

Re: VG Question

Jeff Schussele — Tue, 18 Jun 2002 16:30:02 GMT

Hi (again)

Use the strings command on /etc/lvmtab file - it's a binary file...
strings /etc/lvmtab

dsk => block device (many bytes at once)
rdsk => character device - bytes one after the other.

As a general rule low-level stuff is rdsk & higher level stuff is dsk

Use
pvcreate -f /dev/rdsk/c0t0d2

That should work.

Rgds,
Jeff

Re: VG Question

James R. Ferguson — Tue, 18 Jun 2002 16:33:41 GMT

Hi (again):

Just a note...

You indicated that you used 'more' to view the '/etc/lvmtab' file. You should use the 'strings' command since this file is a binary (not ascii text) file. Your results will be much more readable:

# strings /etc/lvmtab

Regards!

...JRF...

Re: VG Question

PIYUSH D. PATEL — Tue, 18 Jun 2002 16:38:11 GMT

Hi,

/dev/rdsk/c0t0d2 is the raw device ( character device - charcter one after another) and /dev/dsk/c0t0d2 is a block device(many bytes together).

With pvcreate you have to use the raw device.

Piyush

Re: VG Question

Diadina Cotte — Tue, 18 Jun 2002 16:38:16 GMT

yep typo... oh my
root@apache:/dev#>pvcreate -f /dev/rdsk/c0t0d2
Physical volume "/dev/rdsk/c0t0d2" has been successfully created.
root@apache:/dev#>mkdir /dev/vg07
root@apache:/dev#>mknod /dev/vg07 /dev/rdsk/c0t0d2
mknod: arg count
usage: mknod name b|c major minor
mknod name p
root@apache:/dev#>

...well i was going to do this now:

# pvcreate /dev/rdsk/c0t0d2

# mkdir /dev/vg07
# mknod /dev/vg07/group c 64 0x070000

# vgcreate /dev/vg07 /dev/rdsk/c0t0d2

# lvcreate -L size /dev/vg07
# lvcreate -L size /dev/vg07
# lvcreate -L size /dev/vg07

Creates 3 logical volumes lvol1, lvol2 and lvol3

# newfs -F vxfs /dev/vg07/rlvol1
# newfs -F vxfs /dev/vg07/rlvol2
# newfs -F vxfs /dev/vg07/rlvol3

# mount /dev/vg07/lvol1 /extern01
# mount /dev/vg07/lvol2 /extern02
# mount /dev/vg07/lvol3 /extern03

I got stuck in the mknod command
suggestions?
:-(

Re: VG Question

Tal Drigov_1 — Tue, 18 Jun 2002 16:40:39 GMT

Hi,

The devices indeed belongs to an exiting Volume group.
if it's still included in the system you can check via the command:

"strings /etc/lvmtab | grep -i c0t0d2".

if it's not there, then you can force pvcreate by adding the option "-f".

Good Luck.

T.

Re: VG Question

Diadina Cotte — Tue, 18 Jun 2002 16:41:51 GMT

Yep another tipo here ...

Re: VG Question

Tal Drigov_1 — Tue, 18 Jun 2002 16:43:25 GMT

Hey Again,

Where did you got stuck ?
You create the group file via mknod once.

What are you trying to do ?
Just to create a simple VG ? (with lvols)

Re: VG Question

Jeff Schussele — Tue, 18 Jun 2002 16:43:47 GMT

Suspect that the minor # (0x07...) is already in use.

Check the /dev/vg... dirs for it already being used.

Note that you may have to increase the
maxvgs
kernel parameter is it defaults to 10 IF you already have 10 VGs defined.

HTH,
Jeff