Re: Hardware upgrade for a high-traffic database

On Aug 11, 2004, at 3:18 PM, Jason Coene wrote:
>
> I'm wondering why our PG server is using so little memory...  The 
> system has
> 2GB of memory, though only around 200MB of it are used.  Is there a PG
> setting to force more memory usage towards the cache?  Additionally, 
> we use
> FreeBSD.  I've heard that Linux may manage that memory better, any 
> truth
> there?  Sorry if I'm grabbing at straws here :)
>

i don't know about freebsd, but linux is very aggressive about using 
unused memory for disk cache.  we have dedicated linux box running pg 
with 2gb of memory,   about 250mb of memory is being used by processes 
(system+postgres) and shared memory (postgres only), and there is 
1.75gb of disk buffers in use in the kernel.  this particular database 
is only about 4gb, so a good portion of the db resides in memory, 
certainly most of the active set.  the disk subsystem is a 6 disk scsi 
u160 raid array which performs pretty well when there is io.