Hi Sam, we start the pvfs2 servers on different machines than the compute nodes (picking the nodes from the list provided by the batch system). Was that your question?
And I should have said, all the measurements are done with collective I/O of ROMIO. On 7/17/07, Sam Lang <[EMAIL PROTECTED]> wrote:
Ah, I read your email wrong. Hmm...so writes really tank. Are you using the storage nodes as servers, or other compute nodes? -sam On Jul 17, 2007, at 11:15 AM, Sam Lang wrote: > > Hi Florin, > > Just one clarification question...are those are bandwidth numbers > not seconds as the plot label suggests? > > -sam > > On Jul 17, 2007, at 11:03 AM, Florin Isaila wrote: > >> Hi everybody, >> >> I have a question about the PVFS2 write performance. >> >> We did some measurements with BTIO over PVFS2 on lonestar at TACC >> (http://www.tacc.utexas.edu/services/userguides/lonestar/) >> >> and we get pretty bad write results with classes B and C: >> >> http://www.arcos.inf.uc3m.es/~florin/btio.htm >> >> We used 16 I/O servers, the default configuration parameters and upto >> 100 processes. We realized that all I/O servers were used also as >> metadata servers, but BTIO uses just one file. >> >> The times are in seconds, contain only I/O time (no compute time) and >> are aggregated per each BTIO run (BTIO performs several writes). >> >> TroveSyncMeta was set to yes (by default). Could this cause the I/ >> O to >> be serialized? It looks as if there were a serialization. >> >> Or could the fact that all nodes were also launched as metadata >> managers affect the performance? >> >> Any clue why this happens? >> >> Many thanks >> Florin >> _______________________________________________ >> Pvfs2-users mailing list >> [email protected] >> http://www.beowulf-underground.org/mailman/listinfo/pvfs2-users >> >
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