How to increase the disk size online on an HPVM

[KelloggUnixTeam]

Hello,

I have a VM guest running HP UX v11.31 on a host running v11.31 & HPVM v4.2. I have defined the LVs of a VG from the host as vdisks to the guest -

-a disk:avio_stor:lv:/dev/vm_test/rvm1_1
-a disk:avio_stor:lv:/dev/vm_test/rvm1_2

The lv vm1_1 is used for the OS (vg00) and vm1_2 is used as another VG (non vg00). On the host side, I increased the size of the LV (non vg00) and was able to see the size increased. But on the guest side, I was not able to see the disk size increased until I rebooted the guest.

Is it a known problem or am I missing something?

Thanks,
Manjeet

[Steven E. Protter · Accepted solution]

Shalom,

The behavior you are seeing is normal.

On the guest side, can you post the output pre-reboot of:

pvdislay <on the relevant disk>

Normally under HP-Ux extending the size of an already presented lun or disk object is not immediately recognized.

What a lot of shops do is they presnt a new disk to the guest (or system).

They then ioscan -fnC disk or ioscan -fnNC disk

insf -e -C disk # Can cause Oracle RAC permission problems.

At that point there is a new disk provided to a system, even a guest.

Then you can pvcreate/lvextend/extendfs or fsadm (OnlineJFS extend) without a reboot.

Size change is not recognized without a boot, sometimes not even then. New disks are discovered immediately after presentation as a LUN or by the host to the guest.

This disucssion is generic as the concepts apply on systems with hpvm or not. I have a fairly good understanding of HPVM, having run a dozen systems including 1 windows and 1 Linus host on HPVM 4.20 under HP-UX 11.31 in 2010.

SEP

S miley alert: :robotvery-happy:

I'll use them till someone takes them away.

[Richard Hepworth]

Hi,

This pdf on "LVM Volume Group Dynamic LUN Expansion" should help you achieve this:

http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01920387/c01920387.pdf

regards,

Richard

[Eric SAUBIGNAC]

Bonsoir.

Regarding the host versions, HP-UX 11.31 / HPVM 4.20, and the guest version, HP-UX 11.31, it should work.

Until HP-UX 11.31, if the disk size was increased and if the disk was in use (whatever the process that uses it : lvm, direct mount, oracle asm, ...) you didn't saw the new size until there is no more acces to the disk. For example, if the disk was in use by LVM, you had to de-activate the VG to see the new size.

Beginning with HP-UX 11.31 you can see the new size even if the disk is in use. More exactly, even if it used by LVM. For other uses, like oracle ASM, I don't know.

And beginning with HVPM 4.10 (not sure of the version), if the size of an avio backing store is changed, the modification is propagated to the guest.

So are you sure that you didn't did a mistake between the new size of the disk (diskinfo), and the size known by LVM (vgdisplay) ? And with LVM 2.x you can take advantage of the new size of a disk without de-activating the VG that uses it

Eric

[KelloggUnixTeam]

Sorry for the late response!

After some more testing, we decided to present luns from VM Host to the HPVM as avio_stor:disk for all non vg00 VGs.

Thanks to all for their responses!

Manjeet 

[Torsten.]

With HP-UX 11.23 as host system a LVOL as virtual disk was very convenient because of the LVM path redundancy (without additional secure path a disk was only single pathed), but with 11.31 and built-in multipath you can easily use LUNs or disks for the guests without the LVM overhead.

Depending on your update release version of the guest (and maybe use of LVM version 2.x) you can use the online disk increase capability.