HP-UX VM Host combined with production processes

[David G. Douthitt]

We've a newish box with HP-UX 11i v3 ready for when the v3 VM Host support comes out - but we need to use the box (or a box) before then.

If we use the box as a production database server (Intersystems Caché in this instance) will it be possible to turn the system into a VM Host nondestructively (with the goal of moving the production environments into a "real" environment somewhere else)?

If the installation (and creation) of a VM Host is nondestructive, we could go ahead and use the system for production work. Also, would it be possible to take a VM Host disk and turn it into a VM Guest disk with nary a hitch - and no loss of data?

Thanks for the answers!

[Torsten.]

If you read the current manuals up to version 3.50 you will find the recommendations: Use the host only as a host, not for applications.
A VM host disk has the HPVM host software - not allowed on a guest, according to the docs.

[melvyn burnard]

You should NOT use a VM Host server for any production servcies of any application.
If you wish to use it in the interim and then remove that production application, all well and good.

[David G. Douthitt]

Thanks, melvyn - that is closer to the answer I was looking for. Can the data be migrated from a host disk to a virtual disk without loss of data?

[melvyn burnard]

I am uncertain.If the data is on SAN LUN's, using LVM, you could possibly present these LUN's to the VM, create a map file, and then export the VG, and then once on the VM, use these vdisks to create a data vg, using vgimport?
I have never tried this

[David G. Douthitt]

Yes, this would be a SAN disk using LVM. So I should be (might be) able to 1) export the volume group with map; 2) present the volume to the VM (instead of the VH); 3) vgimport the volume group to the VM...

Would step 2 clear the disk in some way?

[Torsten.]

IMHO you need to assign the LUN as a physical disk to the HPVM, not as a LV type backing store.

[David G. Douthitt]

Thanks Torsten.

I was talking about presenting a complete disk with data already on it. The disk would contain data in filesystems (in VxFS and LVM format).

I'm not talking about using an LVM disk to store a VM disk, but rather presenting a disk with data already on it.

More I talk of it, the less preposterous it seems - but will the VM disk manipulator preserve the data?

[Torsten.]

I think a Virtual-to-Physical Cluster will do exactly the same:

http://docs.hp.com/en/T2767-90105/ch11s02.html#app_to_physical_host

[David G. Douthitt]

A virtual-to-physical cluster failover is similar, but it still requires that the disks (and clustering) be set up ahead of time, and requires that the cluster is running.

All of the physical devices would have been set up already, and the disks would have been configured for failover.

It still doesn't answer the main question: is it possible to present a host disk device to the virtual machine without loss of data?

[Torsten.]

IMHO it does answer the question.

If you share a LUN or whatever between a physical server and a HPVM, both must be able to use it. This means, the HPVM host will present this "disk" to the guest - of course without "deleting/modifying" the data.