Forum OpenACS Q&A: How much benefit from dual CPU server? Esp. PostgreSQL

1: How much benefit from dual CPU server? Esp. PostgreSQL

Posted by Louis Gabriel on 08/09/01 07:41 PM

Hi,

Glad to see the site back up! Thanks to all who made it happen.

As most of you know, there is a nice Dual AMD option out there, the
AMD 760MP based Tyan K7 motherboard. From what I've read, there are a
bunch of dual CPU motherboards coming out over the next few months
for both AMD and Intel Pentium III chips.

Intel's new Pentium III Tualatin chip is supposed to become available
in a "server" option with 512K L2 cache, I think.

How much advantage or performance gain do you think the new dual CPU
server options provide? Any "real world" experiences in the
performance and stability areas going from one to two CPUs in a web or
database server?

I'm especially interested regarding PostgreSQL. But also web server
performance and use for a development box.

Tyan is supposed to release a new dual CPU AMD 760MP motherboard for
about $200-$250 very soon. With a $200 price point, it becomes an
interesting option -- even for a development box.

Of course, lots of other issues enter in. Like stability for new
boards and chipsets. While it might take a revision or two to get the
bugs out of the motherboards and BIOS, the dual CPU option sure seems
like an interesting option.

Heck, I wonder how big a bandwidth "pipe" will be needed to take
advantage of the increased performance -- or if there will still be
advantages with a dual CPU server even if one still has the same size
"pipe".

Thanks and take care,

Louis

2: Response to How much benefit from dual CPU server? Esp. PostgreSQL (response to 1)

Posted by Rodger Donaldson on 08/10/01 04:02 AM

Postgresql runs one process per client, so it should take advantage of a multi-processor setup; likewise AOLServer's multithreaded architecture.

The AMD multi-processor architecture has seperate 2.1 GB/s bus per processor; Intel use a single 3.2 GB/s bus shared amongst processors. Which works best will depend on the application, but I'm guessing that for a web/database app aggregate bandwidth is most important (giving AMD the edge as long as you use fast enough RAM and good I/O cards).

Of course, you need to be sure your disk I/O isn't actually your limiting factor.

Speaking of cheap interesting hardware for building solutions with, people may like to take a look at the Promise IDE RAID cases (http://www.promise.com/Products/UltraTrak/UltraTrak100%20TX4%20&%20TX8%20Data%20Sheet.pdf) - up to 8 cheap IDE drives in an external RAID case (hot swap bays and so forth), and an UltraSCSI interface on the back of the box. Cheap RAID with a sensible interface to the server.

3: Response to How much benefit from dual CPU server? Esp. PostgreSQL (response to 1)

Posted by Jamie Ross on 08/11/01 06:47 PM

This is just my own datapoint. I built a dual Celeron 466Mhz system with 786MB RAM and two 80Mbit/s UltraSCSI IBM 9G drives for about $2300 which I run two OpenACS sites and also Oracle8.1.6 on occasion and it seems to handle it fairly well. I don't have a large amount of traffic but it does seem to perform well with the dual processors. I would stress that lots of RAM is a good idea :)

cheers
Jamie