Adding Additional disks to a HPVM Guest

[Kennedy G. Doss]

HP Admins:

When I add disks to a HPVM Guest, I check if the the disks that are being added to the guest are free and available by running:

a) hpvmdevinfo

b) strings /etc/lvmtab

I run both the above commands on the HPVM Host.

If the disks that are being added to the guest are not in the outputs of the above commands is it safe to assume that they are free and available? Any other suggestions? Is this fool-proof enough?

Regards,

-Kennedy.

[Dave Olker]

How are you presenting the disks to the VM?  If you're using NPIV (which I belive you are since you talked about NPIV in a previous thread) then these commands don't guarantee anything.  You could present the same LUNs to a dozen guests at the FC array level and one guest wouldn't know that other guests can see the disks.  You need to be vigilant in how you present your storage, just like you would to physical systems.  That means making sure each VM guest has unique WWNs associated with their virtual HBAs.  HP provides the GUID Manager product to help customers ensure the VM/vPar guests get unique WWNs.  However, even if all VMs have unique WWNs, there's nothing stopping you from presenting the LUNs to multiple guests by mistake and trashing your disks.  Again, this is no different than presenting the same disks to two physical boxes and having them step on each other.

Dave

[Kennedy G. Doss]

Thanks again, Dave. Although we have HP VM 4.3 running we will be using avio_stor and not NPIV/GUID Manager.

Secondly I agree with you - if the disks are accidentally zoned to different physical boxes we have no control over it.

My teammate just gave me a tip. He asked me to run a dd and see if it is in control of LVM, ISL or anyother entity to be double sure anyways. Thought I'd share that with you as well. Here is what I think I will be doing (along with checking lvmtab and running hpvmdevinfo):

# dd if=/dev/rdisk/disk12 bs=1024k count=10 2>&1 | strings | head

10+0 records in

10+0 records out

[For a un-used disk your input and output return with the same number of records)

[For a used disk you may get a similar output)

# dd if=/dev/rdisk/disk13 bs=1024k count=10 2>&1 | strings | head -24

ISL10

LVMREC01

DEFECT01

LVMREC01

DEFECT01

HPLVMBDROA

HPLVMBDROA

ISL

AUTO

HPUX

PAD

LABEL

[Cortes Albertino]

Hi,
"vxdisk list", swapinfo, crashconf, may also be add to your check list if necessary.

Albertino