For installations like yours we would recommend 3 master eligible nodes. This number doesn't need to scale with data volumes as your data nodes do.
A master eligible node should also be dedicated to that task alone - trying to also fulfil search or indexing activities puts them at the risk of becoming unresponsive. We recommend 3 master-eligible nodes because that gives you both a resiliency to failure and a necessary quorum required to avoid split-brain. Fortunately master nodes can be lighter-weight machines than those dedicated to search. Anything less than 3 dedicated master-eligible nodes is essentially an architectural compromise made for smaller-budget configurations. On Wednesday, January 14, 2015 at 9:39:47 AM UTC, Darshat Shah wrote: > > To clarify, the guideline I'm looking for is how many nodes to set apart > as dedicated to be master eligible in a cluster of size N. That is not > N/2+1. > > On Wednesday, January 14, 2015 at 2:24:29 PM UTC+5:30, Darshat Shah wrote: >> >> That's the minimum number. Is it recommended to have more, or will >> elections take longer if we have more than this minimum? >> >> On Wednesday, January 14, 2015 at 2:16:27 PM UTC+5:30, drjz wrote: >>> >>> The formula is N/2+1, so in your case that would be 46 if there are 90 >>> nodes. >>> >>> /JZ >>> >>> On Wednesday, January 14, 2015 at 9:38:01 AM UTC+1, Darshat Shah wrote: >>>> >>>> Hi, >>>> What is the guideline on recommended number of master eligible nodes in >>>> a cluster? >>>> >>>> We have a big cluster with 90+ nodes, currently all are eligible to be >>>> masters. However I do see master election take very long after a cluster >>>> restart - most nodes are still trying to ping the old master and I think >>>> there is no way to force a re-election. >>>> >>>> Will re-election be faster if number of master eligible nodes be less? >>>> Is there a rule of thumb, given N nodes how many should we configure to be >>>> eligible to be masters? >>>> >>>> Thanks >>>> Darshat >>>> >>> -- 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/0e1c31b3-7682-4009-bc79-b46a9c6cda2a%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
