Elasticsearch read and write consistency

Question

Elasticsearch doesn\'t have \"read consistency\" param (like Cassandra). But it has \"write consistency\" and \"read preference\".

Documentation says the following a

Answer 1

Write: I am not sure if above is true for ES 6.1 https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-index_.html#index-wait-for-active-shards says that index operation returns if the primary shard is active and can be changed to other values.

Searches are random so setting wait for active shard field to all will ensure write is successful if it is performed on all shards.

Read: Preference can still be used but it is marked as deprecated.