[jira] [Updated] (YARN-202) Log Aggregation generates a storm of fsync() for namenode
[ https://issues.apache.org/jira/browse/YARN-202?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Vinod Kumar Vavilapalli updated YARN-202: - Issue Type: Sub-task (was: Bug) Parent: YARN-431 > Log Aggregation generates a storm of fsync() for namenode > - > > Key: YARN-202 > URL: https://issues.apache.org/jira/browse/YARN-202 > Project: Hadoop YARN > Issue Type: Sub-task >Affects Versions: 2.0.2-alpha, 0.23.4 >Reporter: Kihwal Lee >Assignee: Kihwal Lee >Priority: Critical > Fix For: 3.0.0, 2.0.3-alpha, 0.23.5 > > Attachments: yarn-202.patch > > > When the log aggregation is on, write to each aggregated container log causes > hflush() to be called. For large clusters, this can creates a lot of fsync() > calls for namenode. > We have seen 6-7x increase in the average number of fsync operations compared > to 1.0.x on a large busy cluster. Over 99% of fsync ops were for log > aggregation writing to tmp files. -- This message was sent by Atlassian JIRA (v6.1#6144)
[jira] [Updated] (YARN-202) Log Aggregation generates a storm of fsync() for namenode
[ https://issues.apache.org/jira/browse/YARN-202?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Kihwal Lee updated YARN-202: Attachment: yarn-202.patch The patch takes out hflush(). I think this is okay, but will appreciate other people's thought on this. > Log Aggregation generates a storm of fsync() for namenode > - > > Key: YARN-202 > URL: https://issues.apache.org/jira/browse/YARN-202 > Project: Hadoop YARN > Issue Type: Bug >Affects Versions: 2.0.2-alpha, 0.23.4 >Reporter: Kihwal Lee >Assignee: Kihwal Lee >Priority: Critical > Attachments: yarn-202.patch > > > When the log aggregation is on, write to each aggregated container log causes > hflush() to be called. For large clusters, this can creates a lot of fsync() > calls for namenode. > We have seen 6-7x increase in the average number of fsync operations compared > to 1.0.x on a large busy cluster. Over 99% of fsync ops were for log > aggregation writing to tmp files. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira
