Re: [PATCH 0/7] dlm: overview

From: Andrew Morton
Date: Mon Apr 25 2005 - 16:26:58 EST

Wim Coekaerts <wim.coekaerts@xxxxxxxxxx> wrote:
> > This is a distributed lock manager (dlm) that we'd like to see added to
> > the kernel. The dlm programming api is very similar to that found on
> > other operating systems, but this is modeled most closely after that in
> > VMS.
> do you have any performance data at all on this ? I like to see a dlm
> but I like to see something that will also perform well. My main concern
> is that I have not seen anything relying on this code do "reasonably
> well". eg can you show gfs numbers w/ number of nodes and scalability ?
> I think it's time we submit ocfs2 w/ it's cluster stack so that folks
> can compare (including actual data/numbers), we have been waiting to
> stabilize everything but I guess there is this preemptive strike going
> on so we might just as well. at least we have had hch and folks comment,
> before sending to submit code.

Preemptive strikes won't work, coz this little target will just redirect
the incoming munitions at his other aggressors ;)

It is good that RH has got this process underway. David, I assume that
other interested parties (ocfs, lustre, etc) know that this is happening?
If not, could you please let them know and invite them to comment?

> Andrew - we will submit ocfs2 so you can have a look, compare and move
> on. we will work with any stack that eventuslly gets accepted, just want
> to see the choice out there and an educated decision.

In an ideal world, the various clustering groups would haggle this thing
into shape, come to a consensus patch series which they all can use and I
would never need to look at the code from a decision-making POV.

The world isn't ideal, but merging something over the strenuous objections
of one or more major groups would be quite regrettable - let's hope that
doesn't happen. Although it might.

> hopefully tomorrow, including data comparing single node and multinode
> performance.

OK. I'm unlikely to merge any first-round patches, as I expect there will
be plenty of review comments and I'm already in a bit of a mess here wrt
patch backlog, email backlog, bug backlog and apparently there have been
some changes in the SCM area...
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