Hi Mohit, I'll answer inline.
On Mon, Apr 28, 2014 at 4:57 PM, Mohit Anchlia <[email protected]>wrote: > >> Trying to understand the following scenarios of consistency in >> elasticsearch: >> >> 1) sync replication - How does elasticsearch deals with consistency issue >> that may arise from 1 node momentarily going down and missing writes to it? >> > This depends on the write consistency setting. By default, the operation only succeeds if a quorum of replicas can index the document: http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/docs-index_.html#index-consistency > When the node comes backup and the reads going to the non-primary shards >> could get inconsistent data? >> > No, when the node comes back up it will sync the stuff it missed with the other nodes. > 2) async replication - What happens if replication is slow for some >> reason, could users see inconsistent data? >> > Yes, if you hit a shard that didn't get the latest operation, it could see an "old" version of the data. You can use "preference" to try and hit the primary shard all the time, but then your replicas will just be sitting there for redundancy: http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/search-request-preference.html > 3) sync/async replication - how does elasticsearch keep data in sync for >> those writes that never happened on the non-primary shard because of >> network/node failures? >> > It either uses the transaction log or it transfers the whole shard to that node. Best regards, Radu -- Performance Monitoring * Log Analytics * Search Analytics Solr & Elasticsearch Support * http://sematext.com/ -- 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/CAHXA0_3aJ4qZt47uyjqs0gd6L1Fz0EhLrV_L7jzSFAYOEvz1Nw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
