[Pvfs2-users] pvfs2 performance with btio

[Sam Lang]

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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