Am Dienstag, 18. Februar 2014 11:24:34 UTC+1 schrieb Jörg Prante: > > With using the quorum of (n/2)+1 you are safe the cluster can always elect > a single leader. > Hm.. not really. 3*2 nodes --- quorum=6/2+1=4 --- a 4 + 2 nodes "split brain" is still possible. And ES stops working, if #nodes<minimum_master_nodes . It would be better to switch ES to a "read only" mode - maybe by introducing a new configuration option similar to minimum_master_nodes.
For multiple DC, running a single cluster without such quorum is high risk > unless you have a reliable network. Why not running several clusters, one > per DC, and syncing them over a slow connection, depending on the > availability of the DCs? > The connection between the DCs is fast and reliable (and expensive, I guess). But pracice shows, that there is no 100% uptime guarantee. Comparable to the reliability of network connections between two racks. ES is already running a regular job for (re-)discovering nodes. > Again - it would be a benefit, if ES is able to detect a split brain situation. Better than keeping the cluster(s) running normally. > If a split brain happened it is too late to resolve, without weird effects > after a rejoin. ES does not mark data operations with a distributed > timestamp protocol so conflict resolution must depend on voting. Such a > voting is not stable. With two halves of a cluster, you may have never a > winner, and data operations could be applied in wrong order. > Agreee. -- You received this message because you are subscribed to the Google Groups "elasticsearch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/elasticsearch/093086bf-af87-49da-9963-60504c5f176d%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
