[ 
https://issues.apache.org/jira/browse/HDFS-11886?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16026504#comment-16026504
 ] 

Anu Engineer commented on HDFS-11886:
-------------------------------------

[~vagarychen]  Just wondering if we should just do what HDFS does. That is if a 
putKey is successful the the OzoneHandler which is talking to the http client 
will also write a success to KSM. That way, when the next time the key is read 
we know if the block is there or not. This will be very similar to block under 
construction notion in HDFS. 

Now there is a question of cleaning up this blocks -- since KSM has metadata 
about these -- the block reports and aging of these records can be combined as 
a parameter for cleaning up/

> Ozone : improve error handling for putkey operation
> ---------------------------------------------------
>
>                 Key: HDFS-11886
>                 URL: https://issues.apache.org/jira/browse/HDFS-11886
>             Project: Hadoop HDFS
>          Issue Type: Sub-task
>          Components: ozone
>            Reporter: Chen Liang
>
> Ozone's putKey operations involve a couple steps:
> 1. KSM calls allocateBlock to SCM, writes this info to KSM's local metastore
> 2. allocatedBlock gets returned to client, client checks to see if container 
> needs to be created on datanode, if yes, create the container
> 3. writes the data to container.
> it is possible that 1 succeeded, but 2 or 3 failed, in this case there will 
> be an entry in KSM's local metastore, but the key is actually nowhere to be 
> found. We need to revert 1 is 2 or 3 failed in this case. 
> To resolve this, we need at least two things to be implemented first.
> 1. We need deleteKey() to be added KSM first. 
> 2. We also need container reports to be implemented first such that SCM can 
> track whether the container is actually added.



--
This message was sent by Atlassian JIRA
(v6.3.15#6346)

---------------------------------------------------------------------
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org

Reply via email to