Hello, On Wed, 14 Nov 2012 23:23:26 +0100 SELS INGENIERIE wrote: > Hi, > > 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. 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. >From network you'll need not only bandwidth, but small latency. Perhaps, IB is your best friend. > 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. 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". Best regards, Andrew Savchenko
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