On 02/06/2014 05:13 PM, Christine Caulfield wrote: > On 05/02/14 16:02, Jan Friesse wrote: >> Chrissie, >> patch looks good but what will happen in following scenario: >>
Unless I made coding errors (entirely possible) in ATB pre-this-patch: >> - 4 nodes (A B C D) and atb list is (A B C D). >> - A B and C D will split. So A B will get quorum right >> - C will split from D both are unquorate at this stage. >> - C will join D. So "previous" partition is C (for D node) and D (for C) C and D are both unquorate. even if they rejoin they will still remain unquorate. ATB should only work: - previous partition was quorate - there is a 50/50 split - partition that has "preferred node" will win. >> node, and as you can see, no A or B. So according to comment, it will >> vote? >> > > Hmm good point. Maybe I need to make the algorithm dependant on the > previous membership list being more (maybe even twice as much) as the > current one. I'll have a think. Unless you changed behaviour in your patch, I am not sure I see the point Jan is trying to make here. Fabio > > Thanks > Chrissie > > >> Honza >> >> Christine Caulfield napsal(a): >>> This patch adds more flexibility to the auto_tie_breaker feature of >>> votequorum. With this, not only can the lowest nodeid be used as >>> a tie breaker, but also the highest, or a node from a nominated list. >>> >>> If there is a list of nodes, the first node in the list that was not >>> part of the previous partition is used. This allows the user to >>> specify a preferred set of nodes but prevents a split-brain if the >>> cluster divides evenly with a node in each half. >>> >>> Signed-Off-By: Christine Caulfield <[email protected]> >>> >>> >>> >>> _______________________________________________ >>> discuss mailing list >>> [email protected] >>> http://lists.corosync.org/mailman/listinfo/discuss >>> >> > > _______________________________________________ > discuss mailing list > [email protected] > http://lists.corosync.org/mailman/listinfo/discuss _______________________________________________ discuss mailing list [email protected] http://lists.corosync.org/mailman/listinfo/discuss
