Messages in this thread | | | Date | Thu, 28 Apr 2005 14:37:20 +0200 | From | Lars Marowsky-Bree <> | Subject | Re: [PATCH 1b/7] dlm: core locking |
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On 2005-04-27T22:52:55, Daniel Phillips <phillips@istop.com> wrote:
> > So we can't deliver it raw membership events. Noted. > > Just to pick a nit: there is no way to be sure a membership event might not > still be on the way to the dead node, however the rest of the cluster knows > the node is dead and can ignore it, in theory. (In practice, only (g)dlm and > gfs are well glued into the cman membership protocol, and other components, > e.g., cluster block devices and applications, need to be looked at with > squinty eyes.)
I'm sorry, I don't get what you are saying here. Could you please clarify?
"Membership even on the way to the dead node"? ie, you mean that the (now dead) node hasn't acknowledged a previous membership which still included it, because it died inbetween? Well, sure, membership is never certain at all; it's always in transition, essentially, because we can only detect faults some time after the fact.
(It'd be cool if we could mandate nodes to pre-announce failures by a couple of seconds, alas I think that's a feature you'll only find in an OSDL requirement document, rated as "prio 1" ;-)
I also don't understand what you're saying in the second part. How are gdlm/gfs "well glued" into the CMAN membership protocol, and what are we looking for when we turn our squinty eyes to applications...?
Sincerely, Lars Marowsky-Brée <lmb@suse.de>
-- High Availability & Clustering SUSE Labs, Research and Development SUSE LINUX Products GmbH - A Novell Business
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