[Lustre-discuss] Lustre, locking, and fsync

[Peter Grandi]

>>> On Mon, 8 Feb 2010 15:45:41 -0600, Robert Olson <olson at mcs.anl.gov> said:

olson> [ ... ] job metadata in an XML file

Sounds like that you are trying to implement a distributed
Lustre backed queueing system. Good luck.

olson> that resides on a Lustre filesystem (I actually just
olson> discovered my running system has it on NFS, but I'm
olson> seeing an anomaly on Lustre so I'll keep writing). [
olson> ... ] all of which have the fs mounted with the flock
olson> option (it falls over immediately without flock). I'm at
olson> lustre 1.6.6.

That mention of "NFS" here is worrying; if you are accessing a
Lustre file via an NFS-Lustre proxy server I suspect you should
be looking into NFS, and anyhow it may not be that reliable.

olson> What I'm seeing is that, occasionally, the file reads
olson> will pick up an empty or partial file. [ ... ]

That seems to be the case as locking is supported in 1.6.6:

  http://lists.lustre.org/pipermail/lustre-discuss/2008-May/007365.html
  http://lists.lustre.org/pipermail/lustre-discuss/2008-May/007366.html