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Linux: High memory utilisation

 
SUDHAKAR_18
Trusted Contributor

Linux: High memory utilisation

Hi,

In one of my linux box consuming high memory.

I have found cache is uilising more. Its a RHEL4 linux.

Please someone help me how to clear cache & how to put threashold to that.

thanks in Advance
3 REPLIES 3
Steven Schweda
Honored Contributor

Re: Linux: High memory utilisation

> I have found cache is uilising more.

Perhaps because no one else wants it.

Normally, disk caching software will release
memory if anyone else wants it. Unused
memory does nothing for anyone, so why do you
want more of it?
dirk dierickx
Honored Contributor

Re: Linux: High memory utilisation

i think this question gets asked 20 times a week. a simple forum search will reveal this and you'll notice the answer to be always the same.

short: it's normal, don't worry about it.
Matti_Kurkela
Honored Contributor

Re: Linux: High memory utilisation

All modern OSs have multiple priority "tiers" for memory allocation.

The number and meaning of each allocation tier varies by OS, but in general, it works like this:

Memory used for disk cache is the lowest possible allocation tier. Memory allocation for applications has higher priority than the cache.

If an application requires memory and free memory is not available, the OS simply finds the least-recently-used cache block and re-allocates it to the application.

If the cache is "dirty" (i.e. contains data that is not yet written to disk), the OS just delays the memory-hungry application a little, sends the cache content to disk, then re-allocates the memory to the application that needed it.

Also remember: if your RHEL4 is a 64-bit version, but the software you're running is 32-bit, the software can never allocate more than 4 GB of RAM.

MK
MK