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Message-ID: <ec6e67fd0705180907g33a15957n89f75aaab85c7c4f@mail.gmail.com>
Date: Fri, 18 May 2007 17:07:43 +0100
From: "James Strachan" <james.strachan@gmail.com>
To: users@activemq.apache.org
Subject: Re: Shared File System Master Slave with OCFS
In-Reply-To: <464DCB8B.20300@ldsys.net>
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References: <10670741.post@talk.nabble.com>
	 <ec6e67fd0705180147w5d6c9fedxae5e5bbc03be93e6@mail.gmail.com>
	 <ec6e67fd0705180153l4190e0afod82bdb542086363c@mail.gmail.com>
	 <464DCB8B.20300@ldsys.net>

On 5/18/07, Christopher G. Stach II <cgs@ldsys.net> wrote:
> James Strachan wrote:
> > On 5/18/07, James Strachan <james.strachan@gmail.com> wrote:
> >> On 5/17/07, felipera <foliveira@livedatagroup.com> wrote:
> >> > Hi everyone,
> >> >
> >> > I am trying to setup two MQ Servers (4.1.1), sharing the same data
> >> directory
> >> > (I tried Derby and Kaha), on top of OCFS, but the locking doesn't
> >> seem to be
> >> > working. It works fine when both MQs are running on the same server
> >> (still
> >> > using OCFS). I see the second MQ waiting for the lock to be released
> >> > ("Journal is locked... waiting 10 seconds for the journal to be
> >> unlocked.").
> >> > That's why I am not sure if it's a OCFS issue. But when I run each
> >> MQ in
> >> > separate boxes (still sharing the same data directory using OCFS) it
> >> doesn't
> >> > work, they both start successfully.
> >>
> >> This is the OCFS you're talking about right?
> >> http://en.wikipedia.org/wiki/OCFS2
> >
> > Actually OCFS2 seems more like a real distributed file system for
> > general purpose use; the OCFS looks more specifically for using to
> > host oracle data tables. Am wondering how good the file locking is on
> > OCFS? Certainly its clear the mutex file locking from Java isn't
> > supported on OCFS.
> >
>
> OCFS2 properly supports POSIX locking semantics with fcntl.  lockf and
> flock aren't supported yet.  If that's what the JVM uses under the
> covers, you're out of luck.  If this is about OCFS and not OCFS2, I'm
> really sorry. :)

Thanks for the heads up! :)

I guess we could make the locking strategy pluggable & we could have
some implementation call the fcntl locking. e.g. maybe using Jtux

http://www.basepath.com/aup/jtux/


-- 
James
-------
http://macstrac.blogspot.com/