From: "J. Bruce Fields" <bfields@fieldses.org>
To: Todd Freeman <freeman@andrews.edu>
Cc: linux-nfs@vger.kernel.org
Subject: Re: Updated files desync and become unlinked
Date: Wed, 23 Nov 2011 15:33:39 -0500 [thread overview]
Message-ID: <20111123203339.GB1044@fieldses.org> (raw)
In-Reply-To: <4EC53D15.3020801@andrews.edu>
On Thu, Nov 17, 2011 at 11:57:57AM -0500, Todd Freeman wrote:
> Good day all...
>
> This may (very likely) be me just misunderstanding a "feature" of
> NFS... but I have a VERY odd behaviour pattern.
>
> We update a set of perl modules on an NFS client (svn update to grab
> new files) we then ssh to another client and restart our apache
> server there and go along our merry way.
> We noticed that the apache server would fairly consistently have an
> old version of the file running and continue running with it until a
> new child started and reread the file (minutes later).
Restarting the apache server should mean apache re-opens the module,
which should be enough for NFS's close-to-open semantics.
If you're exporting ext3 on the server, it could be a time-resolution
problem (ext3 has 1-second resolution timestamps), though I wouldn't
expect that problem to reproduce so quickly.
If you're using NFSv4, it could be a delegation bug; run
echo 0 >/proc/sys/fs/leases-enable
and restart the nfs server to turn them off.
--b.
>
> In debugging this we changed the module so that it checks its .pm
> file with a stat call to see how things are going. The data that we
> got from the stat reflected that the file was still old. We noticed
> that 'ls -al /the/directory/with/the/module/ ' would "fix" the
> desync... but that 'ls -al /the/directory/with/the/module/Module.pm'
> would not. We also noticed that an ls of the file in question would
> show the link count as 0 until it got "fixed", once fixed the link
> count was 1 again.
>
> Am I missing a mount option.. or is there some way around this
> "feature" without doing and ls -alR of the whole thing to make sure
> all the modules are up to date?
>
> My system info:
> Ubuntu 10.10 server
> 2.6.35-30-server #60-Ubuntu SMP Mon Sep 19 21:00:00 UTC 2011 x86_64
> GNU/Linux
>
> nfs-common 1:1.2.2-1ubuntu1.1
>
> Thanks for any help you have to offer.
>
> --
> Todd
> --
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prev parent reply other threads:[~2011-11-23 20:33 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-17 16:57 Updated files desync and become unlinked Todd Freeman
2011-11-23 20:33 ` J. Bruce Fields [this message]
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