[ https://issues.apache.org/jira/browse/HDFS-15759?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Wei-Chiu Chuang updated HDFS-15759: ----------------------------------- Fix Version/s: 3.2.3 > EC: Verify EC reconstruction correctness on DataNode > ---------------------------------------------------- > > Key: HDFS-15759 > URL: https://issues.apache.org/jira/browse/HDFS-15759 > Project: Hadoop HDFS > Issue Type: New Feature > Components: datanode, ec, erasure-coding > Affects Versions: 3.4.0 > Reporter: Toshihiko Uchida > Assignee: Toshihiko Uchida > Priority: Major > Labels: pull-request-available > Fix For: 3.3.1, 3.4.0, 3.2.3 > > Time Spent: 9h 40m > Remaining Estimate: 0h > > EC reconstruction on DataNode has caused data corruption: HDFS-14768, > HDFS-15186 and HDFS-15240. Those issues occur under specific conditions and > the corruption is neither detected nor auto-healed by HDFS. It is obviously > hard for users to monitor data integrity by themselves, and even if they find > corrupted data, it is difficult or sometimes impossible to recover them. > To prevent further data corruption issues, this feature proposes a simple and > effective way to verify EC reconstruction correctness on DataNode at each > reconstruction process. > It verifies correctness of outputs decoded from inputs as follows: > 1. Decoding an input with the outputs; > 2. Compare the decoded input with the original input. > For instance, in RS-6-3, assume that outputs [d1, p1] are decoded from inputs > [d0, d2, d3, d4, d5, p0]. Then the verification is done by decoding d0 from > [d1, d2, d3, d4, d5, p1], and comparing the original and decoded data of d0. > When an EC reconstruction task goes wrong, the comparison will fail with high > probability. > Then the task will also fail and be retried by NameNode. > The next reconstruction will succeed if the condition triggered the failure > is gone. -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org