[HBASE-13170] Allow block cache to be external

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.0
• Fix Version/s: 1.1.0, 2.0.0
• Component/s: io
• Hadoop Flags: Reviewed
• Release Note: HBase can use memcached as an external block cache. To use this change your config to set hbase.blockcache.use.external to true and hbase.cache.memcached.servers to contain the list of memcached servers to use.
• Assignee: Elliott Neil Clark
• Reporter: Elliott Neil Clark
• Created: 07/Mar/15 01:46
• Updated: 03/Jun/15 15:29
• Resolved: 27/Mar/15 20:21

Description

Allow an external service to provide the block cache. This has the nice property of allowing failover/upgrades to happen without causing a fully cold cache.

Additionally this allows read replicas to share some of the same memory.

Issue Links

• relates to: HBASE-13354 Add documentation and tests for external block cache.