topic Re: Cannot create VG on Virtual machine when using raw disk in Operating System - HP-UX

Cannot create VG on Virtual machine when using raw disk

Rajasekhar Raman — Thu, 07 May 2009 19:55:32 GMT

I get the following message while trying to create a VG on integrity VM.

vgcreate: Physical Volume "/dev/dsk/c0t2d0" contains no LVM information

/dev/dsk/c0t2d0 is a "Virtual Disk" that corresponds to a "physical disk/LUN" on the VM host.

IVM version on VM host is 2.0
VMGuestLib version is 3.50

Any help is appreciated.

-Shekar

Re: Cannot create VG on Virtual machine when using raw disk

Robert-Jan Goossens — Thu, 07 May 2009 20:15:56 GMT

Hi Shekar,

did you pvcreate the disk to put the LVM header information on the disk before the vgcreate?

# pvcreate /dev/dsk/c0t2d0

Regards,
Robert-Jan

Re: Cannot create VG on Virtual machine when using raw disk

Tingli — Thu, 07 May 2009 21:00:34 GMT

You can use sam to do the work without much problem.

Also, you host vm version is a little bit old.

Re: Cannot create VG on Virtual machine when using raw disk

Rajasekhar Raman — Mon, 11 May 2009 15:37:21 GMT

I did use "pvcreate" !! I got a "successful" message.

-Shekar

Re: Cannot create VG on Virtual machine when using raw disk

Tingli — Mon, 11 May 2009 15:48:33 GMT

How did you create the disk in the host and send to the guest server?

Re: Cannot create VG on Virtual machine when using raw disk

Rajasekhar Raman — Mon, 11 May 2009 16:30:34 GMT

I assigned a LUN from my SAN to the VM host.

Ran an ioscan, and then an "insf -e" to create the device files.

Then assigned the "disk device" to the guest using:

hpvmmodify -P -a disk:scsi::disk:/dev/rdsk/c0t0d6

On the guest:

Ran an ioscan, and then an insf -e to create the device files.

I saw the disk (/dev/dsk/c0t5d0) on the guest, and "diskinfo" returned the correct size.

I then ran a "pvcreate -f /dev/rdsk/c0t5d0"
which returns:

root@aidjco03:[/]# pvcreate -f /dev/rdsk/c0t5d0
Physical volume "/dev/rdsk/c0t5d0" has been successfully created.

Then ran the following commands:
root@aidjco03:[/]# mkdir /dev/vgtmp
root@aidjco03:[/]# mknod /dev/vgtmp/group c 64 0x030000
root@aidjco03:[/]# vgcreate /dev/vgtmp /dev/dsk/c0t5d0
vgcreate: Physical Volume "/dev/dsk/c0t5d0" contains no LVM information

I am stumped!

Re: Cannot create VG on Virtual machine when using raw disk

Torsten. — Mon, 11 May 2009 16:37:56 GMT

What kind of multipath software does the host run?

Re: Cannot create VG on Virtual machine when using raw disk

Tingli — Mon, 11 May 2009 16:44:43 GMT

What I do would be different from you in the host part.

When I have the device (disk c0t5d0) is ready, I will create a vg from sam. Then (also in sam) created a lv which MUST be unused (or something like that, which is an option in lv creation) This lv won't be mounted to anywhere but its raw device can be assigned to the guest with hpvmmodify.

After that, scan the new disk in from the guest.

Re: Cannot create VG on Virtual machine when using raw disk

Rajasekhar Raman — Mon, 11 May 2009 17:03:51 GMT

I don't have any issues assigning a "lv" from the "VM host". I am trying to assign the physical LUN as I want to reduce the number of layers of operation for the Virtual I/O.

There is no multipathing software on the host. There is only a single path to the LUN from the 'VM host".

-Shekar

Re: Cannot create VG on Virtual machine when using raw disk

Torsten. — Mon, 11 May 2009 17:08:01 GMT

Only a single path to a LUN in SAN? What array is it? What if this single path fails?

Re: Cannot create VG on Virtual machine when using raw disk

Tingli — Mon, 11 May 2009 17:12:45 GMT

Go to /dev/vg and see whether there is a c0t2d0 there. There might be something left and stop the creation. Remove it if there is one.

Re: Cannot create VG on Virtual machine when using raw disk

Rajasekhar Raman — Mon, 11 May 2009 17:44:43 GMT

This is just a test system, so I have no issues with single path. Anyways, that is beyond the scope of this thread.

There are no other device files that may conflict. LIke I said, I am able to read/write to the raw device on the "VM guest", but just not able to create a VG. Am I missing any patches.

I even ensured the VMGuestLib version is 2.0 to be compatible with the VM Host.

-Shekar

Re: Cannot create VG on Virtual machine when using raw disk

Torsten. — Mon, 11 May 2009 17:47:57 GMT

"This is just a test system, so I have no issues with single path. Anyways, that is beyond the scope of this thread."

This depends, especially if you have an active/passive array. Maybe you just have an unsupported environment - I don't know the details.

Re: Cannot create VG on Virtual machine when using raw disk

Rajasekhar Raman — Mon, 11 May 2009 17:59:43 GMT

Do you think that has an impact on the issue at hand?

The storage is on a RAID array which is accessed via SAN fabric. The VM host has only one HBA connected to this fabric. That really should not have an impact correct?

I am not having any problems creating a VG when I use "lv" as the source back storage. Alternately, I don't have an issue when I assign the physical DVD drive as well to the Guest. It is only in the VG creation on the guest that I have a problem.

-Shekar

Re: Cannot create VG on Virtual machine when using raw disk

Torsten. — Mon, 11 May 2009 18:16:48 GMT

It's always hard to suggest something in general without a lot of details like the SAN details (array type) the exact host and guest OS release (date) etc. HPVM 2.0 is AFAIR already unsupported anyway. Maybe patches needed?

Re: Cannot create VG on Virtual machine when using raw disk

Rajasekhar Raman — Tue, 12 May 2009 17:24:00 GMT

I have opened a case with HP support.

Thanks everyone for your help. I will post a resolution once I get it and then close the thread.

In the meanwhile, if anyone has any other ideas, they are welcome.

-Shekar