topic Re: Disabling memory swaping on HPUX 11.31 in Operating System - HP-UX

Disabling memory swaping on HPUX 11.31

GPissutto — Tue, 06 May 2008 16:10:45 GMT

Hello everyone,
I can't find any information telling me how to disable the memory swaping on 11.31, in previous releases it was handled by parameter swapmem_on, which is not longer used by the OS, so I really apreciate any help concerning this issue, I need machine to work with the whole memory for applications.

Best regards,
Cristian.

Re: Disabling memory swaping on HPUX 11.31

Tim Nelson — Tue, 06 May 2008 16:21:59 GMT

First finding from http://docs.hp.com/en/5991-6469/5991-6469.pdf

The tunable swapmem_on has been obsoleted. Pseudo-swap will always be enabled, as
was the default for previous releases of HP-UX.

Re: Disabling memory swaping on HPUX 11.31

Bill Hassell — Tue, 06 May 2008 17:39:05 GMT

Memory swapping is part of any virtual memory system such as HP-UX. If by the term: disable you mean that you do not want swapping to take place at all, then reduce your swap space to less than RAM size. This will cause programs to crash if they do not handle memory limits correctly so you'll not have to worry about swapping. The pseudo_swap concept was a way to allocate RAM without having matching space in the swap area.

> I need machine to work with the whole memory for applications.

This sounds as if you are confused about pseudo_swap. The concept is simply bookeeping. Pseudo_swap is space in RAM for programs and data that do not have a space on the disk. The term is often referred to as memory-based swap but that is quite incorrect. Pseudo_swap simply removes the restriction that every program and data area in RAM must be reserved some place in swap.

All of your memory is available to all of your programs, but if you are running legacy 32bit programs, these programs have extreme limitations on the amount of memory they can use.

Re: Disabling memory swaping on HPUX 11.31

Steven E. Protter — Tue, 06 May 2008 18:30:29 GMT

Shalom Cristian,

I don't think you want to disable it. Swap is necessary for normal OS operation. To avoid swapping you simply throw more memory at the system than it will ever use.

SEP

Re: Disabling memory swaping on HPUX 11.31

GPissutto — Tue, 06 May 2008 19:29:59 GMT

Hello,
First at all, thanks to all of you for quick resonses.
Well, I don't want to disable swaping at all, I just want to know if it is possible disabling the pseudo-swap, as it was possible in the previous hpux releases by setting the swapmem_on parameter to 0. I have been trying to do some research about it without success, so, I don't know if I can do this by setting some new parameters in 11.31 or I just cannot do it at all on 11.31.
Thanks very much again.

Re: Disabling memory swaping on HPUX 11.31

Don Morris_1 — Wed, 07 May 2008 02:26:56 GMT

No, it isn't. The parameter is obsoleted as "man swapmem_on" tells you (and others here). There's no new parameter [it would have been mentioned in the man page], there's no hidden parameter, there's simply no way to turn it off now.

If there's some reason other than idle curiosity you think you wanted to disable it, please state it so your concerns can be addressed.

Re: Disabling memory swaping on HPUX 11.31

Venkatesh BL — Wed, 07 May 2008 03:08:34 GMT

I think the point has been made very clear. Pseudo swap is ON on 11.31 by default, and cannot be turned OFF. There is no reason why you need to worry about it being ON. The applications would only benefit from it.

Re: Disabling memory swaping on HPUX 11.31

GPissutto — Mon, 12 May 2008 03:44:28 GMT

I really apreciate all of your valuable comments and help...thanks very much indeed.