In non "big data" scenarios, having two servers for a database is simply done to achieve high availability. Most databases use a master client scenario, but Elasticsearch does not support such a setup. It really should because not everyone has tons of data.
Ivan, not affiliated with the OP On May 4, 2015 8:32 AM, "Jason Wee" <peich...@gmail.com> wrote: > why must you have only two nodes, would it be possible to add one more > nodes so split brain will not become an issue? > > jason > > On Mon, May 4, 2015 at 2:20 PM, Mark Walkom <markwal...@gmail.com> wrote: > >> Your nodes aren't in different DCs are they? If so this is why we don't >> support such setups, because ES is latency sensitive and these sorts of >> things can happen very easily when your network is unreliable. >> >> They don't try to ping other nodes because you only have two, and if they >> lose contact with one another then they both assume they are masters and >> create their own cluster. Masters don't ping other nodes at random and see >> if they should be joining a different cluster. >> >> Logically there is no difference between a primary and a replica shard, >> the only physical difference is a flag that tells the cluster state which >> is which. This is why ES will never assign a primary and it's applicable >> replica to the same node. >> >> >> You cannot get around the root of your problem unless you add another >> node to and set min masters to ensure a majority quorum. >> >> On 4 May 2015 at 15:27, Gourav H Dhelaria <gouravdhela...@gmail.com> >> wrote: >> >>> >>> 1) After network goes down, they loose communication with each other. >>> After that, they are becoming split. >>> 2) They both think they are masters. Even if they think they are >>> masters, shouldn't the ping happen to see if there are other nodes in the >>> cluster ? >>> 3) Number of replicas is set to 1. If ES doesn't differentiate, why are >>> some shards primary and others replica ? >>> >>> >>> On Monday, 4 May 2015 10:48:24 UTC+5:30, Mark Walkom wrote: >>>> >>>> >>>> 1. Why are they becoming split anyway? GC, other load, network? >>>> 2. Not if they both think they are masters. >>>> 3. Are you running replicas? If so ES doesn't really differentiate >>>> between the two. >>>> >>>> >>>> On 4 May 2015 at 15:03, Gourav H Dhelaria <gouravd...@gmail.com> wrote: >>>> >>>>> Version: 1.4. >>>>> Say there are 2 nodes X and Y, both capable of becoming master. >>>>> When network goes down, both nodes get disconnected from each other >>>>> and assume the responsibility of master. >>>>> When network is restored, they don't ping each other and form a >>>>> cluster. >>>>> >>>>> Elasticsearch service has to be restarted on any one of the nodes for >>>>> them to form a cluster. Even after they form a cluster, all primary shards >>>>> remain on one node ( on which the service was restarted ), and all replica >>>>> shards are on the other node. >>>>> >>>>> >>>>> This document >>>>> >>>>> >>>>> http://www.elastic.co/guide/en/elasticsearch/guide/current/_important_configuration_changes.html >>>>> >>>>> >>>>> mentions that there has to be an uneven number of master eligible >>>>> nodes. >>>>> >>>>> >>>>> Queries: >>>>> >>>>> >>>>> 1) Is there a way of avoiding split brain problem in 2 node cluster ? >>>>> >>>>> 2) After network is restored, shouldn't the nodes ping each other and >>>>> form a cluster ? >>>>> >>>>> 3) After the service is restarted to form the cluster, why don't the >>>>> primary shards get distributed on both the nodes ? >>>>> >>>>> >>>>> >>>>> Thanks, >>>>> >>>>> Gourav >>>>> >>>>> -- >>>>> 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 elasticsearc...@googlegroups.com. >>>>> To view this discussion on the web visit >>>>> https://groups.google.com/d/msgid/elasticsearch/d15234b3-0ea1-4390-b136-2f02f69cd3f5%40googlegroups.com >>>>> <https://groups.google.com/d/msgid/elasticsearch/d15234b3-0ea1-4390-b136-2f02f69cd3f5%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>> . >>>>> For more options, visit https://groups.google.com/d/optout. >>>>> >>>> >>>> -- >>> 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 elasticsearch+unsubscr...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/elasticsearch/bf7a9953-bc87-4b96-843d-7bff5899855f%40googlegroups.com >>> <https://groups.google.com/d/msgid/elasticsearch/bf7a9953-bc87-4b96-843d-7bff5899855f%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- >> 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 elasticsearch+unsubscr...@googlegroups.com. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/elasticsearch/CAEYi1X8nc1A_vmQ_vyG4fq2uNqFA9kZO%2BT_Y4ed0e6wwPM7ztA%40mail.gmail.com >> <https://groups.google.com/d/msgid/elasticsearch/CAEYi1X8nc1A_vmQ_vyG4fq2uNqFA9kZO%2BT_Y4ed0e6wwPM7ztA%40mail.gmail.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> > > -- > 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 elasticsearch+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/elasticsearch/CAHO4itx2SuCKAZHA%2BYjLv4kYGJNN7srx6FVxWJ_UzxzPWZ628w%40mail.gmail.com > <https://groups.google.com/d/msgid/elasticsearch/CAHO4itx2SuCKAZHA%2BYjLv4kYGJNN7srx6FVxWJ_UzxzPWZ628w%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "elasticsearch" group. 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