If the current leader dies, somebody's got to take over. Otis -- Solr & ElasticSearch Support http://sematext.com/
On Mon, Apr 22, 2013 at 9:41 AM, Furkan KAMACI <furkankam...@gmail.com> wrote: > Hi Jack; > > You said: "An hour from now some other replica may be the leader" > > What is the criteria to change a leader of a shard? > > 2013/4/15 Jack Krupansky <j...@basetechnology.com> > >> All nodes are replicas in SolrCloud since there are no masters. It's a >> fully distributed model. A leader is also a replica. A leader is simply a >> replica which was elected to be a leader, for now. An hour from now some >> other replica may be the leader. >> >> It is indeed misleading and inaccurate to suggest that "leader" and >> "replicas" are disjoint. >> >> Once again, I think you are confusing SolrCloud with the older Solr >> master/slave/replication. >> >> Every node in SolrCloud can do indexing. That's the same as saying that >> every replica in SolrCloud can do indexing. >> >> Although we do need to be clear that a given replica will only index >> documents for the shard(s) to which it belongs. >> >> >> -- Jack Krupansky >> >> -----Original Message----- From: Furkan KAMACI >> Sent: Monday, April 15, 2013 9:38 AM >> To: solr-user@lucene.apache.org >> Subject: Re: SolrCloud Leaders >> >> Here writes something: >> >> https://support.lucidworks.com/entries/22180608-Solr-HA-DR-overview-3-x-and-4-0-SolrCloud-and >> >> says: >> >> Both leaders and replicas index items and perform searches. >> >> How replicas index items? >> >> >> 2013/4/15 Furkan KAMACI <furkankam...@gmail.com> >> >> Does leaders may response search requests (I mean do they store indexes) >>> at when I run SolrCloud at first and after a time later? >>> >>> >>> 2013/4/15 Jack Krupansky <j...@basetechnology.com> >>> >>> When the cluster is fully operational, yes. But if part of the cluster is >>>> down or split and unable to communicate, or leader election is in >>>> progress, >>>> the actual count of leaders will not be indicative of the number of >>>> shards. >>>> >>>> Leaders and shards are apples and oranges. If you take down a cluster, by >>>> definition it would have no leaders (because leaders are running code), >>>> but >>>> shards are the files in the index on disk that continue to exist even if >>>> the code is not running. So, in the extreme, the number of leaders can be >>>> zero while the number of shards is non-zero on disk. >>>> >>>> -- Jack Krupansky >>>> >>>> -----Original Message----- From: Furkan KAMACI >>>> Sent: Monday, April 15, 2013 8:21 AM >>>> To: solr-user@lucene.apache.org >>>> Subject: SolrCloud Leaders >>>> >>>> >>>> Does number of leaders at a SolrCloud is equal to number of shards? >>>> >>>> >>> >>> >>
