[Lustre-discuss] Bad read performance

[Brian J. Murrell]

On Thu, 2009-08-20 at 23:52 +0200, Alvaro Aguilera wrote:
> I'm facing the following problem: when this code is run in parallel
> the read operations on certain processes start to need more and more
> time to complete. I attached a graphical trace of this, when using
> only 2 processes. 

Just a (perhaps silly) question, but does the striping of the file (or
the directory the file is being created in) on the filesystem match your
I/O patterns?  That is, ideally, each thread/rank/process (whatever you
want to call them) should be doing I/O in it's own stripe.

$ man lfs

if none of this is meaningful.

b.

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