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Kernel Parameter 100%

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Mohandas
Occasional Advisor

Kernel Parameter 100%

 

Dear All,

 

     We encountered some system kernel parameter 100% usage, can we increase these parameters ? if we do, what is the impact? attached is for your reference. Thanks.

5 REPLIES
Dennis Handly
Acclaimed Contributor

Re: Kernel Parameter 100%

>We encountered some system kernel parameter 100% usage, can we increase these parameters? If we do, what is the impact?

 

This looks like your previous topic:

http://h30499.www3.hp.com/t5/System-Administration/IA64-hp-superdome-server-SD32B-slow-performance/m-p/5303895/message-uid/5303895

 

1) filecache_max

 

This will almost always be 100%, I wouldn't bother increasing it from 3.2 Gb.  Especially if you are using Oracle DB.

 

2) max_thread_proc

 

Is there an application that is aborting and someone wants you to increase it?  1200 seems plenty big enough.

3) maxfiles_lim

 

Same as 2)  4096  But you could double it.

 

Increasing these won't make your system run faster.

James R. Ferguson
Acclaimed Contributor

Re: Kernel Parameter 100%

Hi:

 

You will find that the manpages for the various kernel parameters offer good insight into the affects of raising or lowering the various parameters and the considerations you should ponder.  Read!

 

Regards!

 

...JRF...

Avinash20
Honored Contributor

Re: Kernel Parameter 100%

Refer
http://h30499.www3.hp.com/t5/System-Administration/filecache-max-at-64/td-p/4446286
"Light travels faster than sound. That's why some people appear bright until you hear them speak."
Mohandas
Occasional Advisor

Re: Kernel Parameter 100%

 

Hi Dennis,

 

     I've posted this issue few days back, yes, its my previous topic but this one is more to kernel parameter settings and we have  other questions as well.

 

 We have escalated this issue to HP Support but the reply is not leading anywhere, thats why i posted again to look for some expert advice.

 

1) You have stated thats is fine to increase filecache_max, does this will occupy the system memory more ?

 

2) There are some billing processes dies itself during the execution, does max_thread_proc parameter is controling the amount of processes for all the users ? if yes we are thinking to increase it.

 

3) What does maxfiles_lim do ? i've read several article and i understand its a parameter that allows user processes to execute one single binary program, is that true ?

 

4) How we make the system to run to a optimum level and what are the other factors that control system performance besides Memory and CPU.

 

5) We also enable asynchonous io for the oracle cluster to access the raw device faster, how we can verify whether its working or otherwise ?

 

 

Thanks and Cheers :)

 

 

Dennis Handly
Acclaimed Contributor
Solution

Re: Kernel Parameter 100%

>1) You have stated that's is fine to increase filecache_max, does this will occupy the system memory more?

 

I thought I said the opposite.  If you are running a database you can use the memory better.

 

>2) There are some billing processes dies itself during the execution, does max_thread_proc parameter is controlling the amount of processes for all the users? if yes we are thinking to increase it.

 

That's what I was looking for.  An indication that something was aborting because of the low limits.

It controls the number of threads per process.

Increasing will NOT make your system run faster but it may get your application to work.

 

>3) What does maxfiles_lim do? I've read several article and I understand its a parameter that allows user processes to execute one single binary program, is that true?

 

No.  This is the maximum number of files/sockets, etc that can be opened by the process.  If you need more than this, you may also die.  So you may have to increase it.  Or recode the application to not open so many.

 

>4) How we make the system to run to a optimum level and what are the other factors that control system performance besides Memory and CPU.

 

You have to figure out where the bottlenecks are.

 

>5) We also enable asynchronous I/O for the oracle cluster to access the raw device faster, how we can verify whether its working or otherwise?

 

Measuring performance with glance, sar, vmstat and at a high level, asking users if they notice a difference.