[
https://issues.apache.org/jira/browse/HDFS-1172?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13596083#comment-13596083
]
Uma Maheswara Rao G commented on HDFS-1172:
-------------------------------------------
Hi Todd, Once we convert the file to underConstruction, we are recreating
BlockUnderCOnstruction object if it is already completed right?
{code}
public BlockInfoUnderConstruction convertToBlockUnderConstruction(
BlockUCState s, DatanodeDescriptor[] targets) {
if(isComplete()) {
return new BlockInfoUnderConstruction(
this, getBlockCollection().getBlockReplication(), s, targets);
}
{code}
So, here '==' comparision may create issue here? After this conversion, Even
though it is in underConstruction state it may return false, since block
references might be different from neededReplications list and lastBlock from
InodeFileUnderConstruction?
> 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: namenode
> Affects Versions: 0.21.0
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
> Fix For: 0.24.0
>
> Attachments: HDFS-1172.patch, hdfs-1172.txt, hdfs-1172.txt,
> replicateBlocksFUC1.patch, replicateBlocksFUC1.patch, replicateBlocksFUC.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.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
