topic Re: Message queues in Operating System - HP-UX

Message queues

Yvonne Butler — Mon, 10 Oct 2005 09:36:14 GMT

Hello

We had issues recently on our HP-UX 11.11 system with message queues and our 3rd party application supplier has suggested doubling the parameter related to message queues. Would I be right in thinking the kernel parameter in question would be msgmni? If so, does anyone see a problem in changing its setting from 300 to 600?

Thanks and regards

Re: Message queues

TwoProc — Mon, 10 Oct 2005 09:43:39 GMT

That won't hurt anything to try and see if it eliminates the problem. That number, or msgmax is your problem I would think.

Re: Message queues

Pete Randall — Mon, 10 Oct 2005 09:43:55 GMT

Yvonne,

I would suggest reading through SAM's Help on Configurable Kernel Parameters section on message queues. The message queues are allocated from swappable memory, so doubling the number of them is going to have some impact on memory availability. Take that into consideration when deciding. If you're experiencing any memory pressure now, you're going to want to go slowly here.

Pete

Re: Message queues

A. Clay Stephenson — Mon, 10 Oct 2005 09:46:15 GMT

msgmni might be the correct parameter (and 600 is still not considered a large value) but you might need to increase msgtql, msgseg, and/or msgmnb. There are simply not enough data to make that call yet. The ideal way to know is to capture the errno value and the system call and then you will have a very good notion of the exact limit you are hitting. On the other hand, it is quite safe to increase all of these in a shotgun approach.

Re: Message queues

Yvonne Butler — Mon, 10 Oct 2005 09:48:55 GMT

Before I amend these parameters will increasing them upset Oracle that also runs on this server?

Thanks

Re: Message queues

Piergiacomo Perini — Mon, 10 Oct 2005 09:49:11 GMT

Hi,
I see no big problem in changing "msgmni" but
pay attention because maybe a rebuild of kernel it's needed (and subsequent reboot) and also (if i don't go wrong) some modification
on other (at least one) kernel parameters.

regards

Re: Message queues

Piergiacomo Perini — Mon, 10 Oct 2005 09:55:00 GMT

hi again,
for Oracle: read documentation (precondition)
about your Oracle rdbms version (there
are always the right range for kernel parameters on HP-UX server).

hth
regards

Re: Message queues

Yvonne Butler — Tue, 11 Oct 2005 04:19:02 GMT

Many thanks to everyone for their comments and opinions. I'm going to increase the msgmni parameter and monitor things over the coming weeks. I'll amend others if it becomes apparent that they need changing.

Thanks again!