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Arpit Agarwal commented on HDFS-13818: -------------------------------------- Thanks for filing this [~adam.antal]. It's a great idea to to detect the corruption earlier. The snapshot corruption we saw in HDFS-13314 is detected when the quota compute thread would walk the filesystem tree _after_ the image was successfully loaded. So I think the OIV will have to duplicate the same code paths NameNode executes at startup. Perhaps it will be easier to just try loading the image on another node. > Extend OIV to detect FSImage corruption > --------------------------------------- > > Key: HDFS-13818 > URL: https://issues.apache.org/jira/browse/HDFS-13818 > Project: Hadoop HDFS > Issue Type: Improvement > Components: hdfs > Reporter: Adam Antal > Assignee: Adam Antal > Priority: Major > > A follow-up Jira for HDFS-13031: an improvement of the OIV is suggested for > detecting corruptions like HDFS-13101 in an offline way. > The reasoning is the following. Apart from a NN startup throwing the error, > there is nothing in the customer's hand that could reassure him/her that the > FSImages is good or corrupted. > Although real full checking of the FSImage is only possible by the NN, for > stack traces associated with the observed corruption cases the solution of > putting up a tertiary NN is a little bit of overkill. The OIV would be a > handy choice, already having functionality like loading the fsimage and > constructing the folder structure, we just have to add the option of > detecting the null INodes. For e.g. the Delimited OIV processor can already > use in disk MetadataMap, which reduces memory consumption. Also there may be > a window for parallelizing: iterating through INodes for e.g. could be done > distributed, increasing efficiency, and we wouldn't need a high mem-high CPU > setup for just checking the FSImage. > The suggestion is to add a --detectCorruption option to the OIV which would > check the FSImage for consistency. -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org