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Andrew Purtell commented on HDFS-2576: -------------------------------------- If block device type affinity hints are available, then this could be an additional factor for a future block placement algorithm. See HDFS-2832 and HBASE-6572 for relevant discussion. If device affinity hints might have a path component (e.g. xattr in the namespace that associates a path with a block device type affinity hint), then this could be related here too. A couple of questions fall out: - What of the notion of xattrs in the namespace? - What if xattr handling were pluggable? - Would a favored node hint be a candidate for a plug in handler for an xattr for same? > Namenode should have a favored nodes hint to enable clients to have control > over block placement. > ------------------------------------------------------------------------------------------------- > > Key: HDFS-2576 > URL: https://issues.apache.org/jira/browse/HDFS-2576 > Project: Hadoop HDFS > Issue Type: New Feature > Reporter: Pritam Damania > Attachments: hdfs-2576-1.txt > > > Sometimes Clients like HBase are required to dynamically compute the > datanodes it wishes to place the blocks for a file for higher level of > locality. For this purpose there is a need of a way to give the Namenode a > hint in terms of a favoredNodes parameter about the locations where the > client wants to put each block. The proposed solution is a favored nodes > parameter in the addBlock() method and in the create() file method to enable > the clients to give the hints to the NameNode about the locations of each > replica of the block. Note that this would be just a hint and finally the > NameNode would look at disk usage, datanode load etc. and decide whether it > can respect the hints or not. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira