[Beowulf] SATA II

[Andrew M.A. Cater]

On Tue, Dec 05, 2006 at 12:07:36PM -0500, Mark Hahn wrote:
> >1-Regarding OS, is "Fedora Core 64bit" a good option for AMD Athlon 64 X2
> >4200+?
> 
> sure.  distros are just desktop decoration, and anything recent will 
> perform equally well.  you do probably want 64b, but that's not rare.
> 
Think carefully about what it is you are looking to do. Fedora is 
relatively "bleeding edge" and has a very short lifetime - typically a 
year or 18 months of support. If you are looking to build a large 
cluster, you may want to evaluate something with a longer lifecycle / 
more stability. I will always recommend Debian for this: there is a huge 
amount of software ready packaged but, more importantly, the minimal 
install really is minimal if that is what you want. Debian Etch for 
AMD64 is stable enough for me: it is the current testing release but 
should be released as stable Real Soon Now (it was expected yesterday - 
it may be released as stable by the end of December).

> >2- Is SATA II HDD compatible with Fedora Core 64bit?
> 
> disks don't have compatibility - controllers do.  so it depends on your 
> motherboard choice.  but I haven't seen any builtin controllers that 
> don't work well.
> 
How long is a piece of string? As Mark says, it depends on the 
motherboard controller. Brand new boards may need brand new kernels to 
support the chipset.

> >3- Concerning RAM, is "2 GB 800 MHz DDR2" sufficient?
> 
> any general answer is wrong.  2G is a huge waste of money for some 
> applications, and not nearly enough for others.  you'll pay a noticable 
> premium for ddr2/800 as opposed to ddr2/667, though, and might not 
> notice the difference (again, depending on your workload).
> 
Is interconnect speed a limiting factor or is memory access speed most 
important? Build a toy Beowulf for evaluation from four machines and run 
a subset of your work on it. Where are you sourcing your memory from and 
what premium are you paying if you want to take the cluster down to 
improve memory on the nodes later? Power,environment, cooling and heat 
wise, memory is cheaper and more reliable than spinning hard disks.

> there is only one general correlations I'll draw: many, many 
> loosely-coupled and/or serial jobs have tiny memory footprints (so 2GB is 
> overkill, and since
> the cache is effective, higher bandwidth is wasted).
> 
> it's hard to say anything useful about tighter-than-loose parallel jobs,
> since memory size/intensiveness varies a lot - moreso than for loose/serial,
> at least in my experience...
> 
> regards, mark hahn.
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