Re: Buffer cache not working.

From: Michal Hocko
Date: Tue May 20 2014 - 09:06:04 EST


On Wed 14-05-14 16:46:32, Rogier Wolff wrote:
[...]
> Kernel: from Ubuntu 14.04, 3.13.0-19-generic

The kernel is 64b right?

> 32-bit userspace
> 16Gb RAM installed.
> Disks: 3x 3T in RAID5
>
> ganglia shows the server memory graph as follows:
> http://prive.bitwizard.nl/server_mem.png

This shows that the memory usage didn't go over 5G. That is suspicious.
Is this a NUMA machine? Is it possible that zone_reclaim_mode is enabled
(cat /proc/sys/vm/zone_reclaim_mode)?

> All other computers have a "nice" filled graph there.
>
> So, is there a bug in my kernel or am I missing an important tuning
> parameter?
>
>
> Roger.
>
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--
Michal Hocko
SUSE Labs
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