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Linux buffer cache kernel parameters.

Gulam Mohiuddin
Regular Advisor

Linux buffer cache kernel parameters.

I know in HP-UX we can change OS buffer cache size using dbc_max_pct and dbc_min_pct kernel parameters.

I want to know how to change buffer cache values for RHEL AS 4.0?


Thanks,

Gulam.
Everyday Learning.
4 REPLIES
Ivan Ferreira
Honored Contributor

Re: Linux buffer cache kernel parameters.

Please check this link:

http://www.redhat.com/magazine/001nov04/features/vm/
Por que hacerlo dificil si es posible hacerlo facil? - Why do it the hard way, when you can do it the easy way?
Steven E. Protter
Exalted Contributor

Re: Linux buffer cache kernel parameters.

Shalom,

The default for Red Hat Linux is to set the buffer cache to include almost all free memory.

Contrary to HP-UX, there is no severe performance penalty when taking memory out of the buffer cache and giving it to a process.

My advice is to leave this alone.

In my forums profile is a thread on this topic with more data.

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=1098585

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com
TY 007
Honored Contributor

Re: Linux buffer cache kernel parameters.

Hello Gulam,

dbc_max_pct & dbc_min_pct == HP-UX Specific

Try not mention above HP-UX Parameters in front of your Linux Customer :)

Thanks
dirk dierickx
Honored Contributor

Re: Linux buffer cache kernel parameters.

i don't understand the fixation people have with the buffer usage is linux.

yes, linux takes all memory for buffers that are not in use, that's great (for performance)! at least all that memory is used. believe me, if the kernel would need the memory for other things it won't be used up by buffers.

this costs nothing, but you gain a lot. or would you rather have a lot of memory that is not used? why have that much memory in the first place then?

different OS, different rules.