topic Re: Mixing CPU types in Operating System - HP-UX

Mixing CPU types

Fred Ruffet — Fri, 27 Apr 2007 07:22:34 GMT

Hi !

Till today, I have believed that a single CPU type was requiered on an HP9000 server. I have servers whith PA8500, PA8600 and PA8700 chips. I have just found that one server runs one PA8500 with one PA8600.

As I must recycle old servers in two, I was planning to have one running PA8700 and the other PA8600, using the largest of 4 CPU per server.

Now, what I'd like to know is if there are problems linked to the usage of such a mix, and if there is a way to find what mixes are possible. Is the stronger CPU limited to the weakest's speed ? What rules must be observed ? Which kind of CPU can be used one which type of server ? What documents exist on the subject ?

Any help will be appreciated.

Regards,

Fred

Re: Mixing CPU types

Torsten. — Fri, 27 Apr 2007 07:28:01 GMT

Hi,

normally (and in current servers) mixing CPU types is not supported and won't work.

Some users are running CPUs of the same type but with different speeds together, but at the lowest speed.

So overall, CPUs must be the same type.

Re: Mixing CPU types

Peter Godron — Fri, 27 Apr 2007 07:30:39 GMT

Fred,
have you had a look at this thread:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=965710

All the normal docs state :
"You must not mix CPU modules that include different types of processors."

Re: Mixing CPU types

Fred Ruffet — Fri, 27 Apr 2007 07:39:30 GMT

That's what I was afraid of... It's a production system running with one PA8500 and one PA8600. Looking at L1000 specs, a PA8500 runs 360 or 440 MHz and PA8600 at 540MHz. Server is running for years without a problem, but I can't imagine how this can have been sold.

Thanks,

Fred