[HADOOP-692] Rack-aware Replica Placement

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.10.1
• Fix Version/s: 0.11.0
• Assignee: Hairong Kuang
• Reporter: Hairong Kuang
• Created: 08/Nov/06 18:49
• Updated: 15/Jul/15 20:27
• Resolved: 03/Feb/07 01:11

Description

This issue assumes that HDFS runs on a cluster of computers that spread across many racks. Communication between two nodes on different racks needs to go through switches. Bandwidth in/out of a rack may be less than the total bandwidth of machines in the rack. The purpose of rack-aware replica placement is to improve data reliability, availability, and network bandwidth utilization. The basic idea is that each data node determines to which rack it belongs at the startup time and notifies the name node of the rack id upon registration. The name node maintains a rackid-to-datanode map and tries to place replicas across racks.

Issue Links

• depends upon: HADOOP-937 data node re-registration
• is depended upon by: HADOOP-951 java.util.ConcurrentModificationException in FSNamesystem.chooseTargets
• is depended upon by: HBASE-57 [hbase] Master should allocate regions to regionservers based upon data locality and rack awareness