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Owen O'Malley commented on HDFS-779: ------------------------------------ To address Allen's concern about small clusters, I'd suggest a minimum threshold of 25 nodes being down from the peak. > Automatic move to safe-mode when cluster size drops > --------------------------------------------------- > > Key: HDFS-779 > URL: https://issues.apache.org/jira/browse/HDFS-779 > Project: Hadoop HDFS > Issue Type: New Feature > Components: name-node > Reporter: Owen O'Malley > > As part of looking at using Kerberos, we want to avoid the case where both > the primary (and optional secondary) KDC go offline causing a replication > storm as the DataNodes' service tickets time out and they lose the ability to > connect to the NameNode. However, this is a specific case of a more general > problem of loosing too many nodes too quickly. I think we should have an > option to go into safe mode if the cluster size goes down more than N% in > terms of DataNodes. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.