hadoop-common-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Raghu Angadi (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-3124) DFS data node should not use hard coded 10 minutes as write timeout.
Date Wed, 09 Apr 2008 22:08:06 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-3124?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12587399#action_12587399
] 

Raghu Angadi commented on HADOOP-3124:
--------------------------------------


2 minutes is fine for writes.. though it does not really improve much. Would it matter in
the absence of HADOOP-3132? 

I am more concerned about clients reading from DFS since this timeout current applies to those
connections as well. Currently DFSClient treats these connection failures are real errors
and will try different datanode. I think we need to fix DFSClient before being more aggressive
about this timeout.

0.17 would be the first release that has such a timeout. I am not sure if we should have an
aggressive value. 

That said, I am not strongly opposed to reducing it. 

> DFS data node should not use hard coded 10 minutes as write timeout.
> --------------------------------------------------------------------
>
>                 Key: HADOOP-3124
>                 URL: https://issues.apache.org/jira/browse/HADOOP-3124
>             Project: Hadoop Core
>          Issue Type: Bug
>          Components: dfs
>    Affects Versions: 0.17.0
>            Reporter: Runping Qi
>            Assignee: Raghu Angadi
>         Attachments: HADOOP-3124.patch
>
>
> This problem happens in 0.17 trunk
> I saw reducers waited 10 minutes for writing data to dfs and got timeout.
> The client retries again and timeouted after another 19 minutes.
> After looking into the code, it seems that the dfs data node uses 10 minutes as timeout
for wtiting data into the data node pipeline.
> I thing we have three issues:
> 1. The 10 minutes timeout value is too big for writing a chunk of data (64K) through
the data node pipeline.
> 2. The timeout value should not be hard coded.
> 3. Different datanodes in a pipeline should use different timeout values for writing
to the downstream.
> A reasonable one maybe (20 secs * numOfDataNodesInTheDownStreamPipe).
> For example, if the replication factor is 3, the client uses 60 secs, the first data
node use 40 secs, the second datanode use 20secs.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message