[Pvfs2-users] pvfs2 performance with btio

[Florin Isaila]

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 <slang at mcs.anl.gov> 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
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> >>
> >
>
>