Assembling a database server - which processors to use?

[DWW]

I am having a hard time finding database performance in benchmarks these days. I just want some real numbers about which is better for the job in this case. It will run PostgreSQL most likely.

I've been looking at:
1. Dual AMD MP 2400s
2. Dual Intel Xeon 2.6s
3. Dual AMD Opteron 240s

MPs are the cheapest but have they "expired" ? They use an older/slower bus and can't use faster RAM. AFAIK though, the fastest ECC supported memory is PC2700 ? ECC is a -must-.

The Xeon setup is somewhat cheaper than the Opterons even still.

I'm not that knowledgable in hardware or scaling so I couldn't say which is better performing :\
Thanks for any help.

 

[DWW]

boost

 

[zephyrprime]

Well of course ECC is a must. This is a server after all.

Here are some that I found:

tom's

here's a big list but doesn't seem to have any opteron

some from amd
from anand

It seems to me that both the Xeon and Opteron are alright. But the Opteron could have a big edge in that it allows for more ram and you want to keep as much of your DB cached in memory as possible. But how heavily will your DB be loaded? How many users? And don't overlook the significance of the disk system!!!

 

[DaveSimmons]

^ definitely, RAID 5 plus tape backup and offsite rotation of tapes, if protecting your data is worth anything.

For most applications, protectiong your data well is far more important than squeezing another 5% of performance out of your server.

 

[DWW]

zephyrprime:
Thanks for the links. I guess MySQL is the next best measurement

As for the disk system yes I know that is very important. It is going to average around 20 people concurrently worldwide on average but it could peak higher up to 50 perhaps. I figure the total data repository will store around 20 GB maximum (lots of records for this project).

 

[DWW]

(this is back-of-napkin mathematics we've used so far for users and data storage).

As for data redundancy yes it is very important. RAID mirroring at a minimal with SCSI drives and tape rotation, ECC memory, decent UPS etc.

We are aiming for around 99.5% uptime on the system as per the budget. I don't think that is too unreasonable and allows nearly 48 hours downtime per year.

 

[DaveSimmons]

Only 20 GB?, hmm, just RAID-1 then, 2 x 36 GB SCSI? Not much value in spreading 20 GB over 3+ disks

That's small enough that huge amounts of RAM shouldn't be a key requirement, 2 GB is probably enough since you really only need to cache the index/key information, though if 4 GB is in the budget it might be worthwhile.

 

[DWW]

Dave Simmons: thanks!

I haven't had a whole lot of "big" database experience in the past. I've done smaller VB and ASP .Net projects for Windows but this will be a change.

Next step will be prototyping scenarios with PERL and the database to see what the speeds are like. Unfortunately I have no idea how long I can expect for SELECT statements on larger tables because of my experience (lack thereof).

RAID-1 was the plan so far with some 15k.3 SCSI drives.

I really appreciate these tips because I have no clue how the database requirements translate to hardware :\

 

[DWW]

Is it just me or can anyone else not find information on what toms used for his MySQL test?

 

[DWW]

If toms was any indication I think we might just go with the Opterons because they clearly clean the clock of the others in SELECT