[HDFS-2362] More Improvements on NameNode Scalability

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: namenode
• Assignee: Unassigned
• Reporter: Hairong Kuang
• Created: 26/Sep/11 04:48
• Updated: 10/Jan/14 00:38

Description

This jira acts as an umbrella jira to track all the improvements we've done recently to improve Namenode's performance, responsiveness, and hence scalability. Those improvements include:
1. Incremental block reports (HDFS-395)
2. BlockManager.reportDiff optimization for processing block reports (HDFS-2477)
3. Upgradable lock to allow simutaleous read operation while reportDiff is in progress in processing block reports (HDFS-2490)
4. More CPU efficient data structure for under-replicated/over-replicated/invalidate blocks (HDFS-2476)
5. Increase granularity of write operations in ReplicationMonitor thus reducing contention for write lock (HDFS-2495)
6. Support variable block sizes
7. Release RPC handlers while waiting for edit log is synced to disk
8. Reduce network traffic pressure to the master rack where NN is located by lowering read priority of the replicas on the rack
9. A standalone KeepAlive heartbeat thread
10. Reduce Multiple traversals of path directory to one for most namespace manipulations
11. Move logging out of write lock section.

Sub-Tasks

• More CPU efficient data structure for under-replicated/over-replicated/invalidate blocks: Closed
• Optimize computing the diff between a block report and the namenode state.: Closed
• Upgradable lock to allow simutaleous read operation while reportDiff is in progress in processing block reports: Open
• Increase granularity of write operations in ReplicationMonitor thus reducing contention for write lock: Closed
• A Namenode that keeps only a part of the namespace in memory: Open
• Removing memory limitation of the Namenode by persisting Block - Block location mappings to disk.: Open