Re: [ogfs-dev]GFS of the Linuxtag and OpenGFS

Dominik Vogt <dominik.vogt@xxxxxx> · Wed, 29 Sep 2004 19:31:10 +0200

On Tue, Sep 28, 2004 at 11:29:25AM -0700, Cahill, Ben M wrote:
> Hi Dominik,
> 
> I meant to reply to this a long time ago ... sorry.
> 
> Nice to hear from you!
> 
> Actually, they haven't leveraged the OpenGFS work at all ... they've
> open-sourced the commercial Sistina version, which they've continued to
> improve over the course of time.
> 
> The Redhat GFS/GDLM combination seems pretty stable, and works well ...
> much better than current OpenGFS/OpenDLM combination at present
> (although OpenGFS/memexp seems pretty stable, and works pretty well).
> 
> So, I've pretty much moved over to GFS now, and I don't think that I'll
> be doing anything more to get OpenDLM working with OpenGFS, although we
> were getting pretty close ... the open-source release of the RedHat DLM
> was a big surprise.

> There isn't really any "merging" going on ... about the only things that
> OpenGFS would have to offer would be the external journals (in which
> nobody seems very interested) and documentation, unless you can think of
> anything else.

Sad.  I can't remember the details, but there were quite a couple
of things that we already did in OpenGFS that they want to
duplicate.  If they don't use our code, they're really wasting
time.  I hope they *at least* leverage Alan Cox' audit of the
code.

> I've been adding comments to RedHat code, mostly in .h
> files.  Still might update some of the OpenGFS doc to reflect new GFS
> stuff.  Most of the on-disk layout info is still valid ... thanks again
> for all of your efforts at documenting that ... I've looked at it a few
> times recently.

> The read performance of GFS is not quite as fast as ext3, about 75%
> according to some tests some colleagues did.  And, GFS doesn't seem any
> faster than OpenGFS when doing the untar-the-linux-tarball exercise.  I
> was a little disappointed at that.

As this is a design issue, I'm not surprised.

> Any chance you'll be getting involved with the RedHat stuff??

I asked The RedHat guy at the Linuxtag to get me in contact with
the GFS developers because I wanted to offer my assistace as a
freelance in merging the projects.  I never got any feedback :-P

> > -----Original Message-----
> > From: opengfs-devel-admin@xxxxxxxxxxxxxxxxxxxxx 
> > [mailto:opengfs-devel-admin@xxxxxxxxxxxxxxxxxxxxx] On Behalf 
> > Of Dominik Vogt
> > Sent: Monday, August 09, 2004 4:15 AM
> > To: opengfs-devel@xxxxxxxxxxxxxxxxxxxxx
> > Subject: [ogfs-dev]GFS of the Linuxtag and OpenGFS
> > 
> > A couple of weeks ago, I visited the Linuuxtag 2004 in Karlsruhe
> > (Germany) and listened to a GFS presentation by the RedHat staff.
> > Since they claimed they had already contacted the OpenGFS
> > developers, is assumed they had already informed the mailing list
> > of what they are planning.  Looking archives this seems to have
> > been wishful thinking.
> > 
> > I don't remember all the details anymore, but here is the
> > information I can remember (my comments are in braces).
> > 
> >  * Nobody needs OpenGFS anymore and it is going to vanish.
> >    [Seems to be marketing blabla]
> > 
> >  * The RedHat developers are merging the GFS and OpenGFS projects.
> > 
> >  * They are working on a DLM based lock manager.
> > 
> >  * GFS conforms to POSIX.
> >    [I asked if that means that they fixed the issues that violate
> >    POSIX, e.g. flock() behaviour, but got no answer]
> > 
> >  * GFS has a working redundant lock manager (RLM) which is an
> >    improved version of the old single lock manager (SLM).  Locks
> >    are still managed on a central lock server, but any other node
> >    can become the lock server.  A cluster of lock manager nodes
> >    separate to the cluster of GFS nodes can be used.
> > 
> >  * GFS scales very well.  They claim one of their customers has
> >    a GFS cluster with more than 100 nodes.
> > 
> >  * Reading is as fast as with ext2.
> >    [Marketing lie.]
> > 
> >  * RedHat still supports gnbd, but they are working on iSCSI.
> > 
> >  * The pool driver is going to be replaced with something better.
> > 
> > This all sounds awfully like they are leveraging our work on
> > OpenGFS.  I asked a German RedHat guy to arrange for a contact
> > between me and the GFS developers, but never got a reply.

Ciao

Dominik ^_^  ^_^

 --
Dominik Vogt, dominik.vogt@xxxxxx