hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Tsz Wo (Nicholas), SZE (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-4183) Throttle block recovery
Date Tue, 13 Nov 2012 22:02:13 GMT

    [ https://issues.apache.org/jira/browse/HDFS-4183?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13496594#comment-13496594
] 

Tsz Wo (Nicholas), SZE commented on HDFS-4183:
----------------------------------------------

This problem looks very similar to the large delete problem: the LeaseManager recovers all
expired leases at the same time.  We could limit the number of leases in each iteration and
then we are done since the thread sleeps for NAMENODE_LEASE_RECHECK_INTERVAL between iterations.

> ...  I propose configurable rate with 300/min as default.

I think it is too small but I don't have experimental data to support my argument.
                
> Throttle block recovery
> -----------------------
>
>                 Key: HDFS-4183
>                 URL: https://issues.apache.org/jira/browse/HDFS-4183
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: name-node
>    Affects Versions: 0.23.4, 2.0.2-alpha
>            Reporter: Kihwal Lee
>            Assignee: Kihwal Lee
>            Priority: Critical
>
> When a large number of files are abandoned without closing, a storm of lease expiration
follows in about an hour (lease hard limit). For the last block of each file, block recovery
is initiated and when the datanode is done, it calls commitBlockSynchronization() is called
against namenode. A burst of these calls can slow down namenode considerably. We need to throttle
block recovery and/or speed up the rate at which commitBlockSynchronization() is served.

--
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

Mime
View raw message