[CentOS] Doubled up RAM to 32 GB - now how to speed up a LAPP server?

From: Alexander Farber <alexander.farber at gmail.com>

> I run a small Facebook game at a CentOS 6.3 machine
> with PostgreSQL 8.4.3 + few PHP scripts + 1 Perl daemon
> and even though the server worked ok,
> I've suggested my users to double up the RAM
> to 32 GB and they have collected money for that.
> 
> Now my problem is that I don't know, which knob
> to turn and how to really use the additional memory.
> 
> Below is my top output at the peak time (evenings) -
> as you see, 27 GB of RAM aren't used:
> ...
> I was actually hoping that Linux would use the additional
> memory for caching disks, but this doesn't seem to happen?

Depends on your service...
How much GBs do your database and your files do take?
If you have 100 MB of files, the OS won't cache 30+ GBs...

JD