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<p>Dear FLASH developpers,</p>
<p><br>
</p>
<p>We are running the LaserSlab simulation ( FLASH 4.8 ) on Lustre Filesystem v2.12.5.</p>
<p>When the number of mpi tasks / ode exceed a certain threshold ( typically 100 mpi taks )</p>
<p>the flash4 process hangs during I/O and the lustre working directory in use become not</p>
<p>accessible anymore.</p>
<p>The remaining flash4 are not killable via standard signal and we have to reboot the node in order to</p>
<p>free the ressources.</p>
<p>Do you have any experience of such a problem with Lustre Filesystem ?</p>
<p> </p>
<p>Thanks in advance for any help.</p>
<p>Best regards,</p>
<p>Denis </p>
<p><br>
</p>
<p><br>
</p>
<p>PS: we use the option +hdf5iotype so we are using MPI collective I/O</p>
<p>In attachment to this mail i added a Darshan report about the FLASH I/O performance</p>
<p>on our filesystem </p>
<p><br>
</p>
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<div><span style="font-size:9pt">---------</span><span style="font-size:9pt"></span></div>
<div><span style="font-size:9pt">Denis Bertini</span></div>
<span style="font-size:9pt"></span>
<div><span style="font-size:9pt">Abteilung: CIT</span><br>
<span style="font-size:9pt"></span></div>
<span style="font-size:9pt"></span>
<div><span style="font-size:9pt">Ort: SB3 2.265a</span></div>
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<span style="font-size:9pt"></span></div>
<span style="font-size:9pt"></span>
<div><span style="font-size:9pt">Tel: +49 6159 71 2240</span></div>
<span style="font-size:9pt"></span>
<div><span style="font-size:9pt">Fax: +49 6159 71 2986</span></div>
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<div><span style="font-size:9pt">E-Mail: d.bertini@gsi.de</span></div>
<span style="font-size:9pt"></span>
<div><br>
<span style="font-size:9pt"></span></div>
<span style="font-size:9pt"></span>
<div><span style="font-size:9pt">GSI Helmholtzzentrum für Schwerionenforschung GmbH</span></div>
<span style="font-size:9pt"></span>
<div><span style="font-size:9pt">Planckstraße 1, 64291 Darmstadt, Germany, www.gsi.de</span></div>
<span style="font-size:9pt"></span>
<div><br>
<span style="font-size:9pt"></span></div>
<span style="font-size:9pt"></span>
<div><span style="font-size:9pt">Commercial Register / Handelsregister: Amtsgericht Darmstadt, HRB 1528</span></div>
<span style="font-size:9pt"></span>
<div><span style="font-size:9pt">Managing Directors / Geschäftsführung:</span></div>
<span style="font-size:9pt"></span>
<div><span style="font-size:9pt">Professor Dr. Paolo Giubellino, Dr. Ulrich Breuer, Jörg Blaurock</span></div>
<span style="font-size:9pt"></span>
<div><span style="font-size:9pt">Chairman of the GSI Supervisory Board / Vorsitzender des GSI-Aufsichtsrats:</span></div>
<span style="font-size:9pt"></span>
<div><span style="font-size:9pt">Ministerialdirigent Dr. Volkmar Dietz</span></div>
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