Re: Hardware estimation - Mailing list pgsql-general

> This is also in a rack mount box with dual Hot swappable power supplies,
> it can map out bad memory on the fly automatically, and can provide REAL
5
> 9 reliability.  32 MEGS of L3 cache, 6 megs of L2 cache, PER PROCESSOR.
A
> backend connection with GIGs of data bandwidth per second.  An Intel
based
> box isn't even close to being in the same class.

  And I didn't say that it was in the same class.  You said that it was
about the same price, and I refuted that.  That's all I was saying.  I'm
not a zealot or a devotee of any one class of server, by any means!

> Are these white box prices, or from someone like IBM or Dell?  The best
> price I've seen with that configuration is about $20k. Is that ECC DDR
> memory?

  White-box, and yes, it's registered/ECC DDR.

> Keep in mind, that out of that 8 gigs of ram, only 1.5 or so is gonna be
> available for Postgresql.  The rest will be system cache.  On a 64 bit
> machine you can give as much as you want to the database.

   Actually, any one process will only be able to use the ~1.5 gigs - and
PG forks off new processes for each backend, so you are able to make use
of all 8 gigs - although I do admit that having a larger address space can
be advantageous.

> If you do wanna look at 64 bit systems that are Intel based then Dell
> sells a quad Itanium for a fair price, but by the time you've  upped it
to
> 8 gigs and a pair of 36 gig hard drives, and subtracted their gold star
> on site support, the price is $46k.  For 4 800 MHz CPUs.
>
> A Dell quad Xeon 1.6Gig with 8 gig ram is $29k  IBM is about $20k

   Several years ago, I was in the market for a quad P3 Xeon, and prices
from the "big names" were about the same.  I built one based on a
Supermicro chassis and motherboard for something like $12,000, including a
fairly decent SCSI RAID array.  I've worked with Compaq's servers before,
and haven't seen much advantage.  Yes, they have all of the fancy features
that management thinks are necessary for uptime, but when the rubber meats
the road, the machine I built has run for over two years with absolutely
*NO* downtime other than a few planned shutdowns for planned hardware or
kernel upgrades.  Eventually, it was demoted from production DB server to
developmental server, simply because we needed more horsepower than it
could provide.  (A dual Athlon filled the spot nicely.)

   It should also be noted that simply going to a 64-bit architecture
isn't a magic cure-all.  Right after I built the machine I just spoke of,
a Compaq rep tried to win us over, and loaned us a $25,000 dual-CPU Alpha
for a week.  I ran some PostgreSQL stress tests on it with some of our
production data, and the Xeon handily kept up with or beat the Alpha, at
half of the price.  Now if I was doing some raytracing, I'm sure that the
outcome would have been very different, but for database work, it just
didn't cut it.

   In the end, it's the same argument that gets hashed over in various
forms:  When it comes to commodity vs. specialized hardware, commodity
hardware is always going to be a cheaper way to get things done within the
realm of it's capabilities, but you eventually come to a performance level
where commodity hardware just won't cut it any more.  That's where the
specialized hardware comes in, be it a high-end server like the Power4, a
high-end router for an OC192, or a CAD/CAM graphics card.

steve