[ http://issues.apache.org/jira/browse/HADOOP-64?page=comments#action_12426300 ] Milind Bhandarkar commented on HADOOP-64: -----------------------------------------
I have profiled the namenode, and most action in namenode happens as a response to heartbeat and blockreport messages. Therefore I think it is important to enable the datanode to handle multiple volumes. this also relates to hadoop-50, which needs handling multiple directories. The scheme I have in mind is for datanode to load-balance among volumes (that corrspond to multiple disks) and then within a volume, block-placement will be done within multiple directories according to block-id. I am currently preparing a proposal on this issue. > DataNode should be capable of managing multiple volumes > ------------------------------------------------------- > > Key: HADOOP-64 > URL: http://issues.apache.org/jira/browse/HADOOP-64 > Project: Hadoop > Issue Type: Improvement > Components: dfs > Affects Versions: 0.2.0 > Reporter: Sameer Paranjpye > Assigned To: Konstantin Shvachko > Priority: Minor > Fix For: 0.6.0 > > > The dfs Datanode can only store data on a single filesystem volume. When a > node runs its disks JBOD this means running a Datanode per disk on the > machine. While the scheme works reasonably well on small clusters, on larger > installations (several 100 nodes) it implies a very large number of Datanodes > with associated management overhead in the Namenode. > The Datanod should be enhanced to be able to handle multiple volumes on a > single machine. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
