virtual Machines v/s virtual partitions

[Ali Imran Abbas]

I am just wondering what is the difference between Virtual Partitions (vpar) and virtual machines on Integrity servers. I was browsing the docs.hp.com and I came to know different command sets there.

[melvyn burnard · Accepted solution]

Virtual Partitions allows you to use software and split up an Npar into various smaller servers, and these only run HP-UX. They are configured using whole CPU's, whole LBA's (I/O cards), portions of memory etc. Vpars is also available for both PARISC and Integrity servers.

Virtual Machines is also software, but it runs ONLY on Integrity servers.
You install it onto an HP-UX Integrity server, and it then allows you to create (as it name implies) virtual servers, known as Guests which you can turn on and off, andyou assign virtual cpu's, virtual NIC's and virtual discs to the machine.
You can then boot the virtual machine and install an Operating System, known as the guest OS, onto this machine.
Currentlty the supported Guest OS's are:
HP-UX 11iv2 and 11iv3, Windows 2k3 server, Red Hat and Suse Linux.

You should also note that you cannot have an Npar (server) that has both products installed, they are mutually exclusive.

[Ali Imran Abbas]

Are the CPU's and Memory and other resources shared between guests in VM? In Vpar, we allocate whole cpu and portion of memory, lan cards to the vpar. is that same on vm also or each resource is shared by the guests operating systems?

[melvyn burnard]

all shared in general, although you can assign a physical NIC to a Virtual Switch, and only have one VM Guest use that Switch.
Also, the virtual storage is not shared, although if you use a file as the root disk for a VM, you can have multiple VM "root files" in the same file system, but they are still unique to each VM

[Ali Imran Abbas]

What approach do you suggest to use on integrity servers provided that they will be running hpux only, vpar or vms?

[melvyn burnard]

depends on what you want to use them for.
If you are going to run something that requires fairly intensive I/O, and is going to remain relatively stable, then I would opt for Vpars.

But it is your decision, and you may want to research the applications you wish to run a little further before deciding.

[Eric SAUBIGNAC]

Bonsoir Ali,

A precision about "Also, the virtual storage is not shared" : yes, you can share storage with HPVM. It is just that it is not safe to do that without an arbitrator like MC/ServiceGuard or a cluster file system.

Some readings :

http://forums.itrc.hp.com/service/forums/questionanswer.do?threadId=1199335

In a more general way subforum around virtualization :

http://forums.itrc.hp.com/service/forums/categoryhome.do?categoryId=855

Regards

Eric