topic Re: difference between vpar and npar in Operating System - HP-UX

difference between vpar and npar

khilari — Thu, 31 Jan 2008 20:38:56 GMT

Hi guys, what is the difference between vpar and npar. Would appreciate a short summary rather than been given pdf links.
Thanks

Re: difference between vpar and npar

Tim Nelson — Thu, 31 Jan 2008 20:45:50 GMT

nPar is hard partitioning. i.e. electrically isolated partitions such as with cell based HP systems. A complete failure of 1 cell does not effect the other.

vPar is a softer hard partition, the partitions are not electically isolated but assignment of specifically IO is by LBA ( i.e. by card) a failure of a component could effect another vPar.

I am sure there is a better way to explain. Most likely in the book :)

Re: difference between vpar and npar

Ramesh S — Fri, 01 Feb 2008 07:03:17 GMT

Hi

Npar : Hard partitioning - Partitioned at SBA level -Hardware failure won't affect the other partition

VPar : Soft Patitioning - Partitioned at LBA level : Hardware failure can affect other partition - Software failure wont affect other partition.

Thanks & Regards

Ramesh

Re: difference between vpar and npar

Eric SAUBIGNAC — Fri, 01 Feb 2008 08:45:13 GMT

Bonjour khilari,

Essentials things have been said. Some precisions.

You can have partitionning nPar and/or vPar only with mid-range or high-end boxes, from RX7.../RP7.... to superdome.

nPars ares are electrically isolated from each others. So you can't tink to them in term of independant boxes though they share the same complex.

With nPars granularity is weak : you can't share a cell or an IO chassis between 2 nPars.

You can build vPar in an nPar. An intermediate software between hardware and kernel, /stand/vpmon, will manage nPar hardware and devide it in units to vPar.

Granularity is better : for IO, partionning is done on LBA, you can think to it in term of slot, for CPU it's the core itself, and for memory you can divide to Mo.

For both technologies theres is no sharing of any ressources. They can be used with PA-RISC or Itanium architectures.

There is now a third technology : HP Integrity Virtual Machines. It is Itanium specific and it works on all boxes, from the lowest end to the highest.

This technology permits sharing of ressources like CPU, IO cards, ... If you have heard of VMWare ESX, it's about the same idea ... less enhanced for the moment :-( In ESX the hypervisor is a Linux OS, with Integrity VM it's HP-UX 11iv2.

In an Integrity VM guest, you can have different OS : HP-UX 11iv2, 11iv3, Windows Itanium 64 bits, Linux RH and SL.

You can have HP Integrity VM in an nPar, not in a vPar.

"Would appreciate a short summary rather than been given pdf links." I can understand that but you will find more detailled informations in documentations ;-)

Regards

Eric

Re: difference between vpar and npar

Eric SAUBIGNAC — Fri, 01 Feb 2008 08:49:54 GMT

Sorry, I had some "stammering" with my keyboard ...

"So you can't tink to them in term of independant boxes though they share the same complex"

you must read :

"So you CAN think to them in term of independant boxes though they share the same complex"

No point needed for this clarification

Eric

Re: difference between vpar and npar

Torsten. — Fri, 01 Feb 2008 11:16:25 GMT

A nice introduction:

http://docs.hp.com/en/T1335-90083/ch02s01.html

(it's not a pdf-link)

;-)

Re: difference between vpar and npar

Tim Nelson — Fri, 01 Feb 2008 15:59:12 GMT

One additional note.

I can guarentee you on a rp74xx that with either nPar or vPar in place if you have a VRM ( Voltage Regulator Module ) failure the entire server will come down.

Has happened three times to three different servers over the last 3 years ( hmmm.. 3 must not be a lucky number ).

Re: difference between vpar and npar

Robin T. Slotten — Mon, 04 Feb 2008 21:39:34 GMT

>> For both technologies theres is no sharing of any ressources. They can be used with PA-RISC or Itanium architectures.

Actually, when using vpars, you can share the CPU resources either by manually moving the processors or using WLM to monitor and move CPU resources automatically. I have seen an implementation where they shared CPU across npars using GWLM. This effectively used ICOD processors that GWLM turned on and off depending on the dynamics of the load.

Rob...

Re: difference between vpar and npar

Eric SAUBIGNAC — Wed, 06 Feb 2008 18:55:53 GMT

Robin,

You are perfectly right to underline that we can move CPU ressources between vPars belonging to the same nPar and simulate this move between nPars through deactivation / activation of core cpu unit.

When I said that "theres is no sharing of any ressources" I meant that you can't have nPars or vPars that use at the SAME MOMENT the SAME RESOURCE vs VM technology.

It was just to clarify my post, nothing else, and of course, KHILARI, no point for this post (more exactly assign 0 point to it)

Best regards

Eric