From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Mon, 4 Oct 2004 22:24:43 +0200 From: Lars Marowsky-Bree To: drbd-dev@lists.linbit.com Subject: Re: [Drbd-dev] How Locking in GFS works... Message-ID: <20041004202443.GH1542@marowsky-bree.de> References: <200410041456.21841.philipp.reisner@linbit.com> <20041004134912.GY1542@marowsky-bree.de> <200410041609.23272.philipp.reisner@linbit.com> <200410041617.21258.philipp.reisner@linbit.com> <2AuBE4UNaPcGXlPlToSVgHc=lge@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <2AuBE4UNaPcGXlPlToSVgHc=lge@web.de> List-Id: Coordination of development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 2004-10-04T17:12:24, Lars Ellenberg wrote: > but yes, I think a consistent arbitration would do the trick much > cheaper. For two nodes yes. I think it's the optimal scheme assuming that write contention is not the regular case; if a large percentage (>40% or so) of writes would overlap I assume a coordination algorithm would be better. But, I assume such workloads have a much more fundamental problem. ;-) > though for the (N>2)-node case I'd like to see your paper first ;) I don't think this scheme will work well for >2 node active scenarios if all more than two try to write and receive all writes in different ordering. But >2 nodes would likely wish to have an efficient multicast protocol anyway. Three you could do in a triangle, but 4 already would suck for such a full mesh anyway. Actually, the 2-node active:active seems so straightforward it may make sense for 0.8 already. A passive replication to more than 1 standby may also be doable. >2 node active/active is 0.9 material... I need to add that to our funding plans ;-) Sincerely, Lars Marowsky-Brée -- High Availability & Clustering SUSE Labs, Research and Development SUSE LINUX AG - A Novell company