Le Thu, 15 Nov 2012 04:56:19 +0400, Andrew Savchenko <[email protected]> a écrit :
> Hello, > > On Wed, 14 Nov 2012 23:23:26 +0100 SELS INGENIERIE wrote: > > Hi, Hi, Thanks a lot for your reply, it's a good ressource for me. > > > > I'm looking for Pvfs2 instead of MooseFS. > > > > I read all the documentation, i have installed pvfs2 with success > > but i dont have response for 2 questions > > > > 1/ Distributed Filesystem implies netwoks access, what is the > > network bottleneck ? > > (same question for MooseFS > > http://www.moosefs.org/moosefs-faq.html#mailserver) > > This highly depends on your workload pattern. From our experience on > a 16-nodes 1GBit HPC setup (15 data and meta servers + 16 clients) > OrangeFS is reasonably good for a parallel data access and for large > data chunks per transfer. Ok, you have 15 data server and 1 metadata server. Are you using Heartbeat for redondancy of meta server ? In case of failure on data server, you loose data ? > > On lots of small files or small access data patterns performance > degrades significantly; though work with a large number of small > files may be improved with more metadata servers engaged. very good, it's very interessing. I don't find any documentation on this tips on pvfs web site. therefore, metadata are distribured on metada server or replicate (for hihg avability) > > From network you'll need not only bandwidth, but small latency. > Perhaps, IB is your best friend. > What do you mean by IB ? I don't find IB in doc > > 2/ idem for RAM of metadata server, metadata is stored in RAM and > > flush on disk. > > (same question for MooseFS > > http://www.moosefs.org/moosefs-faq.html#cpu) > > CPU usage is moderate: less than 1 Xeon core in total of a full > gigabit load with 16 parallel clients, but again, this highly depends > on your access pattern. (Though we use heavily optimized entire > system, not just OrangeFS.) I never cared about RAM usage: it is just > low, however you will definitely need as much for local FS cache on > data server as possible. Your mileage may vary, of course. ok. > > However, we do not store metadata in RAM. I really doubt you will > have that much RAM. For small files storage (like program sources) > metadata may take about 25% of your data size. > > > how can i set RAM for 500 Go (for file 50ko) > > I can't understand what do you mean under "Go" and "ko". the RAM in not a bottleneck if i understood your response. Well the size of data server is not link with RAM > > Best regards, Thanks a lot. have a nice day JC PAROLA > Andrew Savchenko -- Nous restons à votre écoute Bien cordialement, Jean-Christophe PAROLA CTO Support Technique / Technical dpt Telephone : +33 4 75 26 20 52 Lundi-vendredi 10-12h & 14-18h30 Télécopie : +33 4 75 26 20 52 http://www.domaine-achat.fr
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