[jira] Commented: (HDFS-1172) Blocks in newly completed files are considered under-replicated too quickly

["dhruba borthakur (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HDFS-1172?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13008665#comment-13008665 ] 

dhruba borthakur commented on HDFS-1172:
----------------------------------------

putting it in pendingReplication means that replication (when needed) will occur only after 5 minutes. This is a long time, isn't it? Maybe it is better to put it in neededReplication but (somehow) ensure that it is not attempted to be replicated until after a small delay.

> Blocks in newly completed files are considered under-replicated too quickly
> ---------------------------------------------------------------------------
>
>                 Key: HDFS-1172
>                 URL: https://issues.apache.org/jira/browse/HDFS-1172
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: name-node
>    Affects Versions: 0.21.0
>            Reporter: Todd Lipcon
>         Attachments: HDFS-1172.patch
>
>
> I've seen this for a long time, and imagine it's a known issue, but couldn't find an existing JIRA. It often happens that we see the NN schedule replication on the last block of files very quickly after they're completed, before the other DNs in the pipeline have a chance to report the new block. This results in a lot of extra replication work on the cluster, as we replicate the block and then end up with multiple excess replicas which are very quickly deleted.

--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira