[HDFS-1520] HDFS 20 append: Lightweight NameNode operation to trigger lease recovery

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.20-append
• Fix Version/s: 0.20-append, 0.20.205.0
• Component/s: namenode
• Hadoop Flags: Reviewed
• Assignee: Hairong Kuang
• Reporter: Hairong Kuang
• Created: 29/Nov/10 21:30
• Updated: 19/Oct/11 00:25
• Resolved: 10/Dec/10 05:39

Description

Currently HBase uses append to trigger the close of HLog during Hlog split. Append is a very expensive operation, which involves not only NameNode operations but creating a writing pipeline. If one of datanodes on the pipeline has a problem, this recovery may takes minutes. I'd like implement a lightweight NameNode operation to trigger lease recovery and make HBase to use this instead.

Issue Links

• blocks: HBASE-3285 Hlog recovery takes too much time
• is related to: HDFS-1186 0.20: DNs should interrupt writers at start of recovery
• relates to: HDFS-1554 Append 0.20: New semantics for recoverLease
• relates to: HDFS-1948 Forward port 'hdfs-1520 lightweight namenode operation to trigger lease reccovery'