From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Philipp Reisner To: drbd-dev@lists.linbit.com Subject: Re: [Drbd-dev] DRBD8: Split-brain false positive on Primary/primary potential patch Date: Thu, 16 Nov 2006 10:10:25 +0100 References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Message-Id: <200611161010.25785.philipp.reisner@linbit.com> Cc: "Montrose, Ernest" List-Id: Coordination of development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Am Dienstag, 7. November 2006 00:47 schrieb Montrose, Ernest: > When running Primary/Primary if the Heartbeat connection goes down when > we recover we always split brain. Simon had an idea which I have > implemented. He is on vacation so this may not reflect his exact idea. > > Essentially with this change, we do not create a new current UUID on the > node unless I/O is seen. This prevent Split-Brain mitigation when both > nodes are primary but only one node is originating I/O and never the > other. He is only stand-by in that case. > > Take a look and let me know. Hi Ernest, I understand your reasoning, I see the patch, which I guess does=20 what you expect of it. I do not want to do it that way for the following reasons: * It is only applicable in case you are using a 1-node filesystem on a primary-primary DRBD cluster. * I do not want users to do this. Because with this setup it is easily possible to mount the FS on both nodes concurrently. I want to protect the from themselfs ;) * Users using a 1-node filesystem should use DRBD withe=20 primary and secondary role. * I rather want to fix DRBD's split brain recovery methods to deal with a cluster crash of a primary-primary cluster (actually this is item 41 in the ROADMAP file) I have a few hours time today, I will work on this today...=20 =2DPhil =2D-=20 : Dipl-Ing Philipp Reisner Tel +43-1-8178292-50 : : LINBIT Information Technologies GmbH Fax +43-1-8178292-82 : : Sch=F6nbrunnerstr 244, 1120 Vienna, Austria http://www.linbit.com :