Shailendra Mudgal wrote: > Hi, > I have some data in a filesystem. Now because of some problem. my > hadoop is > not starting. Is there a way to get the contents of that filesystem ??
Your previous post indicates that your FS got corrupted - specifically, a list of namespace edits is inconsistent, because there is an edit op recorded that concerns a location, for which there is no record of its parent dir being created.. These edit operations are stored in an "edits" file, which represents a sort of diff against the last recorded snapshot of the filesystem (itself stored in "fsimage" file). These edits are merged into fsimage only during namenode startup sequence - apparently there is some corruption there, and the namenode cannot merge this edits file into fsimage. There are ways to fix this "edits" file, but it's quite hard - it involves using a binary editor, and finding record boundaries by hand, and then removing offending edits, or adding an explicit edit to create the parent dir. There is another way too, if you are prepared to lose some data - that is, all data created / modified during the last period when the cluster was up, because that's when the last checkpoint (merge) of the fsimage occurred. The edit log is stored in namenode in a file called "edits". If you shut down the cluster, remove this file, and restart the cluster, the FS should come back healthy - but all data created/modified during the last period will be lost (datanodes will start to physically remove all blocks that are not accounted for in the current fsimage). If it's any consolation - this problem is recognized, and people are actively working on fixing it. -- Best regards, Andrzej Bialecki <>< ___. ___ ___ ___ _ _ __________________________________ [__ || __|__/|__||\/| Information Retrieval, Semantic Web ___|||__|| \| || | Embedded Unix, System Integration http://www.sigram.com Contact: info at sigram dot com ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Nutch-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/nutch-general
