[ https://issues.apache.org/jira/browse/HDFS-2171?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Eric Payne updated HDFS-2171: ----------------------------- Release Note: New dfsadmin command added: [-setBalancerBandwidth <bandwidth>] where bandwidth is max network bandwidth in bytes per second that the balancer is allowed to use on each datanode during balacing. Status: Patch Available (was: Open) > Changes to balancer bandwidth should not require datanode restart. > ------------------------------------------------------------------ > > Key: HDFS-2171 > URL: https://issues.apache.org/jira/browse/HDFS-2171 > Project: Hadoop HDFS > Issue Type: Bug > Components: balancer, data-node > Affects Versions: 0.20.205.0 > Reporter: Eric Payne > Assignee: Eric Payne > Fix For: 0.20.205.0 > > Attachments: HDFS-2171.patch > > > Currently in order to change the value of the balancer bandwidth > (dfs.datanode.balance.bandwidthPerSec), the datanode daemon must be restarted. > The optimal value of the bandwidthPerSec parameter is not always (almost > never) known at the time of cluster startup, but only once a new node is > placed in the cluster and balancing is begun. If the balancing is taking too > long (bandwidthPerSec is too low) or the balancing is taking up too much > bandwidth (bandwidthPerSec is too high), the cluster must go into a > "maintenance window" where it is unusable while all of the datanodes are > bounced. In large clusters of thousands of nodes, this can be a real > maintenance problem because these "mainenance windows" can take a long time > and there may have to be several of them while the bandwidthPerSec is > experimented with and tuned. > A possible solution to this problem would be to add a -bandwidth parameter to > the balancer tool. If bandwidth is supplied, pass the value to the datanodes > via the OP_REPLACE_BLOCK and OP_COPY_BLOCK DataTransferProtocol requests. > This would make it necessary, however, to change the DataTransferProtocol > version. -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira