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Todd Lipcon commented on HDFS-3004: ----------------------------------- Can you add a release note field for this issue, with brief description of the new feature and a pointer to the docs that describe it? > Implement Recovery Mode > ----------------------- > > Key: HDFS-3004 > URL: https://issues.apache.org/jira/browse/HDFS-3004 > Project: Hadoop HDFS > Issue Type: New Feature > Components: tools > Reporter: Colin Patrick McCabe > Assignee: Colin Patrick McCabe > Fix For: 2.0.0 > > Attachments: HDFS-3004.010.patch, HDFS-3004.011.patch, > HDFS-3004.012.patch, HDFS-3004.013.patch, HDFS-3004.015.patch, > HDFS-3004.016.patch, HDFS-3004.017.patch, HDFS-3004.018.patch, > HDFS-3004.019.patch, HDFS-3004.020.patch, HDFS-3004.022.patch, > HDFS-3004.023.patch, HDFS-3004.024.patch, HDFS-3004.026.patch, > HDFS-3004.027.patch, HDFS-3004.029.patch, HDFS-3004.030.patch, > HDFS-3004.031.patch, HDFS-3004.032.patch, HDFS-3004.033.patch, > HDFS-3004.034.patch, HDFS-3004.035.patch, HDFS-3004.036.patch, > HDFS-3004.037.patch, HDFS-3004.038.patch, HDFS-3004.039.patch, > HDFS-3004.040.patch, HDFS-3004.041.patch, HDFS-3004.042.patch, > HDFS-3004.042.patch, HDFS-3004.042.patch, HDFS-3004.043.patch, > HDFS-3004__namenode_recovery_tool.txt > > > When the NameNode metadata is corrupt for some reason, we want to be able to > fix it. Obviously, we would prefer never to get in this case. In a perfect > world, we never would. However, bad data on disk can happen from time to > time, because of hardware errors or misconfigurations. In the past we have > had to correct it manually, which is time-consuming and which can result in > downtime. > Recovery mode is initialized by the system administrator. When the NameNode > starts up in Recovery Mode, it will try to load the FSImage file, apply all > the edits from the edits log, and then write out a new image. Then it will > shut down. > Unlike in the normal startup process, the recovery mode startup process will > be interactive. When the NameNode finds something that is inconsistent, it > will prompt the operator as to what it should do. The operator can also > choose to take the first option for all prompts by starting up with the '-f' > flag, or typing 'a' at one of the prompts. > I have reused as much code as possible from the NameNode in this tool. > Hopefully, the effort that was spent developing this will also make the > NameNode editLog and image processing even more robust than it already is. -- 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