[ http://issues.apache.org/jira/browse/HADOOP-171?page=comments#action_12376622 ]
Doug Cutting commented on HADOOP-171: ------------------------------------- > We can implement short highReplicationHint() That would work, but it doesn't seem like the simplest API. But if folks feel strongly I can live with it. > Then copyFromLocalFile() would use that value to create files. I don't think we want copyFromLocal to always do that. I think we'd end up with something like: fs.setReplication(fs.highReplicationHint()); That's okay. If the filesystem grows or shrinks a lot then it might become inadequate. But whatever, if most folks prefer this, I'd be willing to go along. Perhaps we need to distingush in the API between the requested replication count and the actual replication count. Then one can set the requested level to Small.MAX_VALUE and query the actual value to see how the fs interprets this. > need standard API to set dfs replication = high > ----------------------------------------------- > > Key: HADOOP-171 > URL: http://issues.apache.org/jira/browse/HADOOP-171 > Project: Hadoop > Type: New Feature > Components: dfs > Versions: 0.2 > Reporter: Doug Cutting > Assignee: Konstantin Shvachko > > There should be a standard way to indicate that files should be highly > replicated, appropriate for files that all nodes will read. This should be > settable both on file creation and for already-existing files. Perhaps > specifying a particular replication value, like Short.MAX_VALUE, or zero, can > be used to signal this. The level should not be constant, but should be > relative to the cluster size and network topography. If more nodes are added > or if nodes are deleted, the actual replication count should increase or > decrease. > Initially, all that is needed is an API to specify this. It could initially > be implemented with a constant (e.g., 10) or with something related to the > number of datanodes (sqrt?), and needn't auto-adjust as the cluster size > changes That is only the long-term goal. > When JobClient copies job files (job.xml & job.jar) into the job's > filesystem, it should specify this replication level. -- 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
