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From: Dave Hysom <hysom1@llnl.gov>
To: lustre-devel@lists.lustre.org
Subject: [Lustre-devel] extremely slow reads at 1024 procs
Date: Tue, 14 Jun 2011 16:45:59 -0700	[thread overview]
Message-ID: <4DF7F2B7.1010606@llnl.gov> (raw)

All,

I've just joined to list and will be searching the archives in case
this has been addressed before -- so please point me to a past
thread as appropriate.

Scenario:

We have ~100K files.  Each is 8Mb.  Each is read once, by a single
processor, using fread.  Once we reach a certain number of processors
(512 or 1024) some of the reads take enormous amounts of time, up to
15 minutes.  Our files have stripe=2, which I'm told should be adequate.
Our application is I/O intensive.

Has anyone had similar experience, and/or have a clue what might be
going on, and/or let me know what additional details I should include?

thanks, David

             reply	other threads:[~2011-06-14 23:45 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-14 23:45 Dave Hysom [this message]
2011-06-15 19:10 ` [Lustre-devel] extremely slow reads at 1024 procs wangdi

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