On 01/09/2013 07:42 AM, Jörg Saßmannshausen wrote: > Dear all, > > Happy New Year! > > I was wondering whether people on the list here have some first hand > experiences with this. I have been asked to purchase a single machine with > around 500 GB of RAM. We would not need more than 8 cores here. The job simply > needs that much of memory (and even then it is running for 14 days).
We've built/delivered/supported machines with 1+TB before. They aren't too uncommon these days, and you have a number of choices w.r.t. them. If you can share more about the specific nature of the calculation, you'd likely get better recommendations. That is, large memory, light/no threading could be a very large matlab job (we've seen this) among other things. This would impact CPU choice as well as RAM speed choices. And this gets to a more design focused discussion as well. You can build a single machine with this much ram, or aggregate multiple machines with vSMP from ScaleMP and use somewhat less expensive RAM. > > Now, with that amount of memory used by a single core, I would have thought > that I need a fast memory interconnect, i.e. a high memory bandwidth. I was > thinking of getting an Intel Sandybridge CPU (maybe a E5-2650) for that > machine and get a motherboard with can cope with that amount of memory. Does > anybody happen to have some recommendations here or knows of potential > pitfalls? Don't design the system too early without a better discussion of the process. Apart from being memory bound, are you CPU bound? IO bound? Network bound? > > Also, in a related problem, how would I set the kernel.shmmni, kernel.shmall > and kernel.shmmax values so I am not running out of memory handles here. I am > still confused by that. > > Any kind of advice here is much appreciated. Given it is an expensive piece of > hardware we want to purchase I want to get it right. > > All the best from a grey London > > Jörg > -- Joseph Landman, Ph.D Founder and CEO Scalable Informatics Inc. email: land...@scalableinformatics.com web : http://scalableinformatics.com http://scalableinformatics.com/sicluster phone: +1 734 786 8423 x121 fax : +1 866 888 3112 cell : +1 734 612 4615 _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
