topic Re: Linux buffer cache kernel parameters. in Operating System - Linux

Linux buffer cache kernel parameters.

Gulam Mohiuddin — Thu, 15 Nov 2007 10:44:51 GMT

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.

Re: Linux buffer cache kernel parameters.

Ivan Ferreira — Thu, 15 Nov 2007 11:00:55 GMT

Please check this link:

http://www.redhat.com/magazine/001nov04/features/vm/

Re: Linux buffer cache kernel parameters.

Steven E. Protter — Thu, 15 Nov 2007 12:25:00 GMT

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

Re: Linux buffer cache kernel parameters.

TY 007 — Thu, 15 Nov 2007 20:55:08 GMT

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

Re: Linux buffer cache kernel parameters.

dirk dierickx — Fri, 16 Nov 2007 04:12:49 GMT

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.