Re: free RAM not being used for page cache

On Wed, Jul 30, 2014 at 12:51 PM, Kevin Goess <kgoess@bepress.com> wrote:
> A couple months ago we upgraded the RAM on our database servers from 48GB to
> 64GB.  Immediately afterwards the new RAM was being used for page cache,
> which is what we want, but that seems to have dropped off over time, and
> there's currently actually like 12GB of totally unused RAM.
>
> http://s76.photobucket.com/user/kgoesspb/media/db1-mem-historical.png.html
>
> Is that expected?  Is there a setting we need to tune for that?  We have
> 400GB of databases on this box, so I know it's not all fitting in that
> 49.89GB.

could be a numa issue.  Take a look at:
http://frosty-postgres.blogspot.com/2012/08/postgresql-numa-and-zone-reclaim-mode.html

merlin