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<div>The flock locks (and regular LDLM locks for Lustre metadata and data extents) are reconstructed from client state if the MDS or OSS crash. </div>
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Cheers, Andreas</div>
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On Nov 26, 2017, at 21:03, John Bent <<a href="mailto:johnbent@gmail.com">johnbent@gmail.com</a>> wrote:<br>
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<div>How does the lock manager avoid disk IO? Locks don’t survive MDS0 failure?</div>
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On Nov 26, 2017, at 8:29 PM, Dilger, Andreas <<a href="mailto:andreas.dilger@intel.com">andreas.dilger@intel.com</a>> wrote:<br>
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<div>The flock functionality only affects applications that are actually using it. It does not add any overhead for applications that do not use flock. </div>
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<div>There are two flock options:</div>
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<div> - localflock, which only keeps locking on the local client node and is sufficient for applications that only run on a single node</div>
<div>- flock, which adds locking between applications on different clients mounted with this option. This is if you have a distributed application that is running on multiple clients that controls its file access via flock (e.g. Producer/consumer). </div>
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<div>The overhead itself depends on how much the application is actually using flock. The lock manager is on MDS0, and uses Lustre RPCs (which can run at 100k/s or higher), and does not involve any disk IO. <br>
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<div>Cheers, Andreas</div>
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On Nov 26, 2017, at 12:03, E.S. Rosenberg <<a href="mailto:esr+lustre@mail.hebrew.edu">esr+lustre@mail.hebrew.edu</a>> wrote:<br>
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<div>Hi Torsten,<br>
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Thanks that worked!<br>
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Do you or anyone on the list know if/how flock affects Lustre performance? <br>
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Thanks again,<br>
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<div>Eli<br>
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<div class="gmail_quote">On Tue, Nov 21, 2017 at 9:18 AM, Torsten Harenberg <span dir="ltr">
<<a href="mailto:torsten.harenberg@cern.ch" target="_blank">torsten.harenberg@cern.ch</a>></span> wrote:<br>
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Hi Eli,<br>
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Am 21.11.17 um 01:26 schrieb E.S. Rosenberg:<br>
<span class="">> So I was wondering would this issue be solved by Lustre bindings for<br>
> Java or is this a way of locking that isn't supported by Lustre?<br>
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</span>I know nothing about Elastic Search, but have you tried to mount Lustre<br>
with "flock" in the mount options?<br>
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Cheers<br>
<span class="HOEnZb"><font color="#888888"><br>
Torsten<br>
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--<br>
<><><><><><><><><><><><><><><><wbr><><><><><><><><><><><><><><><><wbr><><><><br>
<> <><br>
<> Dr. Torsten Harenberg <a href="mailto:Torsten.Harenberg@cern.ch">Torsten.Harenberg@cern.ch</a> <><br>
<> Bergische Universitaet <><br>
<> Fakutät 4 - Physik Tel.: <a href="tel:%2B49%20%280%29202%20439-3521" value="+492024393521">
+49 (0)202 439-3521</a> <><br>
<> Gaussstr. 20 Fax : <a href="tel:%2B49%20%280%29202%20439-2811" value="+492024392811">
+49 (0)202 439-2811</a> <><br>
<> 42097 Wuppertal @CERN: Bat. 1-1-049 <><br>
<> <><br>
<><><><><><><>< Of course it runs NetBSD <a href="http://www.netbsd.org" rel="noreferrer" target="_blank">
http://www.netbsd.org</a> ><><br>
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