npar vs. vpar

[derek b smith_1]

Hi! I have a few questions that I did not see in any of the existing threads:

on an 8400 can I use an npar with a vpar or vpars?
can I use npars with vpars?
why would I want to use an npar over vpar?
why would I want to use vpar over an npar?

What are the advantages of vpars?

I know npar are hard partitions and vpars are logical but when does it make more sense to use vpars vs. npars?

thank you
derek

[Pete Randall · Accepted solution]

Derek,

First of all, yes, you can have vpars within npars. Secondly, I would say the big difference is that the vpars are more dynamic in terms of altering your allocations for memory, I/O and CPU.


Pete

[Robert-Jan Goossens]

Ferek,

Check this link.

http://www.software.hp.com/portal/swdepot/displayProductInfo.do?productNumber=T1335AC

Regards,
Robert-Jan

[Florian Heigl (new acc)]

if You want to run a highly productive system free of any external influence (possible issues: outstanding reconfiguration "BIB", cell board failures hitting multiple systems, NUMA performance loss), chose NPAR, if You want to be flexible and have short (faster reboots, more dynamic allocation) downtimes, chose VPARs.

Don't get me wrong: I've never seen any unscheduled downtime due to VPARs, and we run a lot of them. I'd only chose a NPAR for the highest-productive systems, where nothing shall be at risk.

VPAR give You great benefits, especially if You dare to dig into the features. i.e. rolling lanless backups of multiple databases with low hardware overhead by simply mapping one cpu and fc-hba around.

[derek b smith_1]

thanks the link was all I needed! : )

[Duncan Edmonstone]

The thing about vPars is that any 'floating' processor (i.e. a processor that can be moved from one vPar to another) is unable to carry out any IO operations. This is due to the fact that the current version of HP-UX does not support migration of IO interrupts off a running processor. This functionality is coming to vPars some time Q2 this year, but as things stand, any floating processors will not do any IO for you.

What does this mean? Well what it means in practice is you *need* to benchmark your application performance both with and without floating processors to get a good feel for performance - could be your parcticular IO profile will not be impacted by this issue, or it could be it severely reduces your throughput - you MUST test before deploying in a vPar config.

Just my $0.02 worth

Duncan