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<div class="moz-cite-prefix"><font size="-1"><b>On 04/16/2018 11:25
PM, Wei-keng Liao wrote:</b></font><br>
</div>
<blockquote type="cite"
cite="mid:D0384D70-D564-4203-9035-10304A9846CF@eecs.northwestern.edu">
<blockquote>
<div class=""><font color="#003333">Using NFS is discouraged for
MPI-IO (and PnetCDF as well) applications, because</font></div>
<div class=""><font color="#003333">it requires a special
setting in NFS lock daemons to make it work correctly for
MPI-IO.</font></div>
<div class=""><font color="#003333">See ROMIO user guide at <a
href="ftp://ftp.mcs.anl.gov/pub/romio/users-guide/node12.html" class=""
moz-do-not-send="true">ftp://ftp.mcs.anl.gov/pub/romio/users-guide/node12.html</a></font></div>
</blockquote>
<blockquote>
<div class=""><font color="#003333">If the HPC cluster you are
using has a parallel file system, such as Lustre or</font></div>
<div class=""><font color="#003333">OrangeFS, then you should
use it.</font></div>
</blockquote>
</blockquote>
<p>Wei-keng -- my sysadmin's tell me that NFS is all that we're ever
going to have on our cluster.<br>
I can live with substandard I/O performance, I just want the
various I/O libraries to give the right data.<br>
We can try following these ROMIO instructions, but can you answer
some questions about it?<br>
</p>
<p>1) It says that ROMIO is used in MPICH. Just to confirm, do
MVAPICH2 & OpenMPI & Intel/MPI all use ROMIO?<br>
And even if not, would the instructions still be relevant to
these other MPI's?<br>
</p>
<p> 2) It talks about NFS version 3. It looks like we have a
combination of 3 & 4 on our system.<br>
Are the instructions relevant to NFS version 4?<br>
</p>
<p>3) Given the reservations about performance, I suppose I could
ask for a special directory to be created & mounted for
"coherent" operations, and leave the other mounts as-is.<br>
Do you see any problems with doing this?</p>
<p>Thanks,</p>
<p> Carl</p>
<p><br>
</p>
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