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Uma Maheswara Rao G commented on HDFS-2713: ------------------------------------------- Hi Todd/ ATM, Before moving, i wanted to know your opinions on this proposal. > HA : An alternative approach to clients handling Namenode failover. > -------------------------------------------------------------------- > > Key: HDFS-2713 > URL: https://issues.apache.org/jira/browse/HDFS-2713 > Project: Hadoop HDFS > Issue Type: Sub-task > Components: ha, hdfs client > Affects Versions: HA branch (HDFS-1623) > Reporter: Uma Maheswara Rao G > Assignee: Uma Maheswara Rao G > > This is the approach for client failover which we adopted when we developed > HA for Hadoop. I would like to propose thia approach for others to review & > include in the HA implementation, if found useful. > This is similar to the ConfiguredProxyProvider in the sense that the it takes > the address of both the Namenodes as the input. The major differences I can > see from the current implementation are > 1) During failover, user threads can be controlled very accurately about *the > time they wait for active namenode* to be available, awaiting the retry. > Beyond this, the threads will not be made to wait; DFS Client will throw an > Exception indicating that the operation has failed. > 2) Failover happens in a seperate thread, not in the client application > threads. The thread will keep trying to find the Active Namenode until it > succeeds. > 3) This also means that irrespective of whether the operation's RetryAction > is RETRY_FAILOVER or FAIL, the user thread can trigger the client's failover. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira