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Hairong Kuang commented on HADOOP-692: -------------------------------------- I decide to ask data nodes to register after a name node restarts. To avoid the rack-aware patch to become to bulky, I created a separate issue HADOOP-937 to address the data node re-registration. > Rack-aware Replica Placement > ---------------------------- > > Key: HADOOP-692 > URL: https://issues.apache.org/jira/browse/HADOOP-692 > Project: Hadoop > Issue Type: Improvement > Components: dfs > Affects Versions: 0.8.0 > Reporter: Hairong Kuang > Assigned To: Hairong Kuang > Attachments: rack.patch, Rack_aware_HDFS_proposal.pdf > > > 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. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.