Hello! Just to be perfectly clear here - Solr has advantage over ElasticSearch because it can split the live index. However, this sentence from Jack's mail is not true:
"In other words, even though you can easily “add shards” on ES, those are really just replicas of existing primary shards and cannot be new primary shard" The replicas can become new primary shards if something happens to a primary shard - this is similar to what SolrCloud supports. -- Regards, Rafał Kuć Sematext :: http://sematext.com/ :: Solr - Lucene - ElasticSearch > Correct. > ES currently does not let you change the number of shards after you've > created an Index (Collection in SolrCloud). > It does not let you split shards either. SolrCloud has an advantage > over ES around this at this point. > Otis > -- > Solr & ElasticSearch Support -- http://sematext.com/ > Performance Monitoring -- http://sematext.com/spm > On Fri, Jul 5, 2013 at 6:51 PM, Jack Krupansky <j...@basetechnology.com> > wrote: >> According to the ElasticSearch glossary, “You cannot change the number of >> primary shards in an index, once the index is created.” Really? Is that >> true? (A “primary shard” is what Solr calls a shard, or slice.) >> >> In other words, even though you can easily “add shards” on ES, those are >> really just replicas of existing primary shards and cannot be new primary >> shards – if I understand that statement correctly. Besides the simple fact >> that if a primary shard goes down, a non-primary shard can be promoted to >> being a primary shard (“a replica shard can be promoted to a primary shard >> if the primary fails.”) >> >> See: >> http://www.elasticsearch.org/guide/reference/glossary/ >> >> My understanding is that with Solr you can do things like split shards and >> change the number of shards per node. Is this an advantage that ES does not >> offer? >> >> Any ES experts want to comment? >> >> -- Jack Krupansky
