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Hudson commented on HDFS-8873: ------------------------------ SUCCESS: Integrated in Hadoop-Yarn-trunk #1183 (See [https://builds.apache.org/job/Hadoop-Yarn-trunk/1183/]) HDFS-8873. Allow the directoryScanner to be rate-limited (Daniel Templeton via Colin P. McCabe) (cmccabe: rev 7a3c381b39887a02e944fa98287afd0eb4db3560) * hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml * hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestDirectoryScanner.java * hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java * hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt * hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DirectoryScanner.java > Allow the directoryScanner to be rate-limited > --------------------------------------------- > > Key: HDFS-8873 > URL: https://issues.apache.org/jira/browse/HDFS-8873 > Project: Hadoop HDFS > Issue Type: Improvement > Components: datanode > Affects Versions: 2.7.1 > Reporter: Nathan Roberts > Assignee: Daniel Templeton > Fix For: 2.8.0 > > Attachments: HDFS-8873.001.patch, HDFS-8873.002.patch, > HDFS-8873.003.patch, HDFS-8873.004.patch, HDFS-8873.005.patch, > HDFS-8873.006.patch, HDFS-8873.007.patch, HDFS-8873.008.patch, > HDFS-8873.009.patch > > > The new 2-level directory layout can make directory scans expensive in terms > of disk seeks (see HDFS-8791) for details. > It would be good if the directoryScanner() had a configurable duty cycle that > would reduce its impact on disk performance (much like the approach in > HDFS-8617). > Without such a throttle, disks can go 100% busy for many minutes at a time > (assuming the common case of all inodes in cache but no directory blocks > cached, 64K seeks are required for full directory listing which translates to > 655 seconds) -- This message was sent by Atlassian JIRA (v6.3.4#6332)