Re: most bang for buck with ~ $20,000 - Mailing list pgsql-performance

On Tue, 2006-08-08 at 15:43, Kenji Morishige wrote:
> I've asked for some help here a few months ago and got some really helpfull
> answers regarding RAID controllers and server configuration.  Up until
> recently I've been running PostgreSQL on a two year old Dual Xeon 3.06Ghz
> machine with a single channel RAID controller (previously Adaptec 2200S, but
> now changed to LSI MegaRAID). The 2U unit is from a generic vendor using what
> I believe is a SuperMicro motherboard.  In the last week after upgrading the
> RAID controller, the machine has had disk failure and some other issues. I
> would like to build a very reliable dedicated postgreSQL server that has the
> ultimate possible performance and reliabily for around $20,000.  The data set
> size is only currently about 4GB, but is increasing by approximately 50MB
> daily.  The server also requires about 500 connections and I have been
> monitoring about 100-200 queries per second at the moment.  I am planning to
> run FreeBSD 6.1 if possible, but I am open to any other suggestions if it
> improves performance.

This really depends on your usage patterns.

OLAP or OLTP workloads?  Do you need 24/7 reliability and therefore a
two machine setup?  There's a lot of variety in load.

Generally, you spend your money on disks, then memory, then CPU, in that
order.

Look at the Areca cards, they've come highly recommended here.  Look at
LOTS of drives.  Given the size of your db, you can go with LOTS of
smaller drives and get good performance.  If you can find a good box to
hold 12 to 16 drives and fill it with 37 gig 15k RPM drives, you'll have
lots of storage, even in RAID 1+0 config.  That's aiming at
transactional throughput.

Toss as much memory as is reasonably affordable at it.  That's normally
in the 4 to 8 gig range.  After that things start to get expensive fast.

Multiple - dual core CPUs are a good idea.  Opterons seem to be better
"data pumps" with large memory and >2 CPUs than Intels right now.
Better to have a 2xdual core opteron with slower processors than a
single dual core or dual single core CPU(s) with a faster clock speed.
As long as the memory access is equivalent, the more CPUs the better in
Opterons, where their interconnect speed increases as you increase the
number of CPUs.  Intel Xeons are the opposite.  Better with fewer faster
CPUs / cores.

I just ran through a configurator on a site selling quad dual core
opteron servers.  8 Seagate cheetah 15k rpm drives, 8 gig ram, and the
slowest (1.8 GHz) AMD dual core CPUs (4 of them) for 8 cores, came out
to $13,500 or so.

I'd take the other $7.5 grand and buy a backup server that can old as
much but isn't quite as beefy and set up slony to have a live hot spare
sitting ready.  Oh, and maybe to buy some spare parts to sit in the desk
drawer in case things break.