[SOLR-13405] Support 1 or 0 replicas per shard

• Type: New Feature
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Assignee: Unassigned
• Reporter: Yonik Seeley
• Created: 15/Apr/19 16:32
• Updated: 08/Jun/19 15:00

Description

When multiple replicas per shard are not needed for data durability (because of shared storage support on HDFS or S3, etc), other cluster configurations suddenly make sense like allowing 1 or even 0 replicas per shard (primarily to lower costs.)

One big issue with a single replica per shard is that zookeeper (and thus the overseer) waits for a session timeout before marking the node as down.  Instead of queries having to wait this long (~30 sec), if a SolrJ query client detects that a node died, it can ask the overseer to quickly bring up another replica.

Issue Links

• relates to: SOLR-13101 Shared storage via a new SHARED replica type