Semaphore Errors

[Vito Sarducci]

We have this application called Cloverleaf. Its a messaging transmission software package between servers that moves HL7 data from one server to another. Were having problems configuring the kernel parameters.

Each time we configure the kernel parameters, the application pukes and has numerous semaphore error messages.

We have been rangling with the application developers who support this package and to no avail have we been able to determine what best kernel parameters work for this applications?

Any ideas would be appreciated?

Vito

[Michael Tully]

Please post a copy of the current kernel parameters.

Thanks

[Ross Martin]

Your system is complaining about semaphore resources -- then it means that you will most likely want to increase them.

semaem default is 16,384
semmap default is (semmni + 2)
semmni default is 64
semmns default is 128
semmnu default is 30
semume default is 10
semvmx default is 32767

Now, some of these parameters interact with other kernel parameters.

Start with the parameters at their defaults, then increase by about 10 percent until the errors go away or change to something specific. Just don't exceed the maximums or you won't be able to generate a new kernel using SAM.

Semaphores are basically traffic cops, if the intersection gets into a traffic jam, then it slows down the launching of processes.

Twon documents that you can get from the ITRC might help with performance and tuning:

1. KBRC00000947 System Performance Tuning Guide

2. A4460661 Basics of Poor System Performance

Hope that helps,

Ross Martin
HP Response Center

[Ross Martin]

One other thought, when you get into SAM -> Kernel Parameters -> Configurable Parameters

Check "Help on Context" for each semaphore related parameter -- it will show you the min/max and defaults -- it will also show you what effect and interaction it has with other kernel parameters.

Don't adjust all the semaphore parameters at once, start by reading what their function is and how it applies to the error message you are getting. Change only what is necessary (one or two parameters at a time) until the message goes away.

As you can tell, this is a trial and error process.

Ross

[S.K. Chan]

Without the details of the error it is going ot be difficult to determine what kernel parameters to tune or even conclude if this is related to kernel at all.