Sorry about not responding to the whole list earlier - this is my first time 
posting to a mailing list.

Would providing more information about the size and complexities of the 
databases help?

I measure I/O stats with iostat - here is the command I use:

iostat -d -x mfid0 -t 290 2

I tried looking at the man page for iostat but couldn't find anywhere how to 
determine what the stats are for sequential vs random - any help there?

When using 'top -m io' the postgres stats collector process is constantly at 
99% - 100%.

When using 'top' the WCPU for the postgres stats collector and the autovacuum 
process are constantly at 20% - 21%.

Is that normal?  It seems to me that the stats collector is doing all the I/O 
(which would mean the stats collector is doing 46.1 megabytes /sec).

Also, the I/O stats don't change hardly at all (except at night during backups 
which makes sense).  They don't go up or down with user activity on the server 
- which makes me wonder a little bit.  I have a feeling that if I just turned 
off Apache that the I/O stats wouldn't change.  Which leads me to believe that 
the I/O is not query related - its stats collecting and autovacuuming related.  
Is that expected?

It seems to me that the stats collector shouldn't be using that much I/O and 
CPU (and the autovacuum shouldn't be using that much CPU)  - therefore 
something in my configuration must be messed up or could be changed somehow.  
But maybe I'm wrong - please let me know.

I don't think my setup is necessarily slow.  I just want to make it as 
efficient as possible and wanted to get some feedback to see if am setting 
things up right.  I am also looking out into the future and seeing how much 
load I can put on this server before getting another one.  If I can reduce the 
I/O and CPU that the stats collector and autovacuum are using without losing 
any functionality then I can put more load on the server.

Again thanks for all the help.

Scott Otis
CIO / Lead Developer
Intand
www.intand.com

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