Re: linux /proc/sys/vm/pagecache for oracle

From: Fabrizio Magni <fabrizio.magni_at_mycontinent.com>
Date: Thu, 06 Apr 2006 09:27:37 +0200
Message-ID: <4434c2e9$0$22410$892e7fe2@authen.yellow.readfreenews.net>

NetComrade wrote:

>> In general, on any 2.6 kernel (not only redhat), you should use 
>> /proc/sys/vm/swappiness.
>>

>
>
> This looks to be a parameter affecting swapping processes, not file
> system caching.
>
> Anyway, my 'cached' file systems seem to be not the ones oracle is
> sitting on, as when I remounted in 'direct' cache didn't go away. The
> fie system is vxfs and we are using ODM, so nothing should be cached..
> which is why I was confused that cache is so big.

Swappiness indicates how aggressive pages in memory are swapped out, even for fs cached pages, which is probably what you wish to avoid.

It automates what the second parameter of pagecache was meant to do.

As far as I remember /proc/sys/vm/pagecache was a 2.2 kernel features and redhat ported it on kernel 2.4 with AS 2.1. It has been dropped a long time ago.

Never used ODM on linux so I cannot help you there. Sorry.

Regards

-- 
Fabrizio Magni

fabrizio.magni_at_mycontinent.com

replace mycontinent with europe

Received on Thu Apr 06 2006 - 02:27:37 CDT