Re: [MLUG] buying a nice Linux server

[Jack Smith <EMAIL:PROTECTED>]

----- Original Message ----

> From: Mike Miller <EMAIL:PROTECTED>
> To: MLUG membership <EMAIL:PROTECTED>
> Sent: Friday, September 26, 2008 6:41:28 PM
> Subject: [MLUG] buying a nice Linux server
> 
> I'm going to start looking for a good Linux server pretty soon.
> 
> I bought something from Dell about five years ago:
> 
> http://taxa.epi.umn.edu/~mbmiller/mlug/linuxbox.html
> 
> We actually dropped the second disk before ordering because we planned to 
> connect to a disk array by fiber optic cable.  Never did it though and now 
> need to buy a second disk (SCSI costs way more than SATA!).
> 
> I will be doing a lot of database work on this machine.  It will need lots 
> of disk space and probably lots of RAM (e.g., 12 GB?), multiple CPUs, and 
> I think 64-bit architecture and 64-bit Linux OS.
> 
> So what do you think is the way to go?
> 
> Also, we'll want to run Oracle on it, which might require certain choices 
> in Linux distro, but I'm not sure on that -- anyone know anything?
> 
> Mike

I know some about making high-performance computers to do things like run R/Octave/MATLAB, computerized fluid dynamics calculations, and various other number-crunching programs. Here are a few bits of advice and suggestions:

My biggest piece of advice is to keep the number of sockets on a single motherboard down to the smallest number and still have enough cores to get the job done. This is because the price of motherboards and otherwise-equivalent processors goes up by a huge amount with an increasing number of sockets per board. An example:

Processor = AMD K10 2.3 GHz quad-core, 4x512 KB L2 cache, 2 MB L3 cache
1. Single socket: Phenom X4 9650, $155
2. Dual socket: Opteron 2356, $690
3. Quad/eight socket: Opteron 8356, $1555

Motherboards are similar. A reasonable single-socket AM2+ motherboard is under a hundred bucks, a dual socket F board is about $300, and a quad socket F board is about a grand. If you use Intel processors, the frontside bus is a shared bus and performance degrades as you add more CPUs. A single quad-core Xeon works very nicely and scales from one to four threads nicely, but add a second CPU and you see rather poor scaling as you try to use the fifth, sixth, seventh, and eighth threads.Thus I really do not recommend getting Intel server CPUs. AMD's Opterons have several independent CPU-to-CPU links and memory controllers in each CPU, so you do not see bus traffic start to overwhelm the system until you move beyond four sockets (as in that case the CPUs cannot talk directly to each other but through neighboring CPUs.) IIRC, Oracle has a per-socket licensing fee, so keeping the number of sockets down keeps more money in your pocket.

All current desktop and server CPUs are 64-bit capable, so no worries about supporting 64-bit OSes. Almost all CPUs or motherboards also support 4 GB memory modules. Single-socket desktop systems typically have four slots (16 GB). Intel dual socket 771 servers have four to 16 slots (16-64 GB), and AMD dual/quad/8-way servers have four to eight memory slots per CPU. 

So I'd recommend first looking at a standard desktop system with a quad-core CPU (Intel or AMD, it doesn't matter much) and three or four 4 GB DDR2 modules. If you need more cores, then look at dual socket F Opteron machine with two quad-core Opterons. If you need more than eight cores, you'd most likely be better off at looking at setting up a cluster of single-socket desktop machines than buying a quad-socket machine as they are going to cost at least $5000 to build (and that's not a particularly fast one.)

I hope this helps. 

--Jack



      

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