[ https://issues.apache.org/jira/browse/HDFS-8873?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14791470#comment-14791470 ]
Hadoop QA commented on HDFS-8873: --------------------------------- \\ \\ | (x) *{color:red}-1 overall{color}* | \\ \\ || Vote || Subsystem || Runtime || Comment || | {color:red}-1{color} | pre-patch | 15m 49s | Findbugs (version ) appears to be broken on trunk. | | {color:green}+1{color} | @author | 0m 0s | The patch does not contain any @author tags. | | {color:green}+1{color} | tests included | 0m 0s | The patch appears to include 1 new or modified test files. | | {color:red}-1{color} | javac | 2m 3s | The patch appears to cause the build to fail. | \\ \\ || Subsystem || Report/Notes || | Patch URL | http://issues.apache.org/jira/secure/attachment/12756379/HDFS-8873.003.patch | | Optional Tests | javadoc javac unit findbugs checkstyle | | git revision | trunk / 0832b38 | | Console output | https://builds.apache.org/job/PreCommit-HDFS-Build/12499/console | This message was automatically generated. > throttle directoryScanner > ------------------------- > > 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 > Attachments: HDFS-8873.001.patch, HDFS-8873.002.patch, > HDFS-8873.003.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)