Re: [PATCH 1a/7] dlm: core locking

From: Daniel Phillips
Date: Fri Apr 29 2005 - 03:10:41 EST

On Thursday 28 April 2005 13:19, Joel Becker wrote:
> On Thu, Apr 28, 2005 at 02:48:57PM +0100, Stephen C. Tweedie wrote:
> > reduce the latency for this case. My gut feeling, though, is that I'd
> > still prefer to see the DLM doing its work properly, cluster-wide in
> > this case, as precaution against accidents if we get inconsistent states
> > on disk leading to two nodes trying to create the same lock at once.
> > Experience suggests that such things *do* go wrong, and it's as well to
> > plan for them --- early detection is good!
> And unacceptably slow. With LKM_LOCAL, OCFS2 approaches ext3
> speed untarring a kernel tree, because everything under the toplevel
> directory is a candidate for LKM_LOCAL. Network communication may be
> fast, but pagecache operations are even faster. I don't know by how
> much, but I bet if we turned off LKM_LOCAL in the OCFS2 DLM, we'd lose a
> lot of speed.

Why don't you try it, and post the numbers?


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