[
https://issues.apache.org/jira/browse/HDFS-8137?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14521585#comment-14521585
]
Uma Maheswara Rao G commented on HDFS-8137:
-------------------------------------------
Thanks a lot for the review Kai.
Good catch. You are right, we are storing in xattrs along with zone.
{quote}
ECSchemaManager might not be supposed to get a schema associated with a zone,
dir/file, but ErasureCodingZoneManager may do.
{quote}
By mistake I said as ECSchemaManager. Your are right, I should have said as
ErasureCodingZoneManager as it has that related code what I was talking.
Also I added the getECSchema API in namesystem itself as we have already added
some ECSchema related API in FSNameSystem. For reusing the codes from
ECZoneManager codes, keeping this new API in namesystem would give us the
flexibility, but we can not get the same flexibility from BlockCollection as we
can not access FSDirectory details there.
Please check if the latest patch make sense for you?
> Sends the EC schema to DataNode as well in EC encoding/recovering command
> -------------------------------------------------------------------------
>
> Key: HDFS-8137
> URL: https://issues.apache.org/jira/browse/HDFS-8137
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Kai Zheng
> Assignee: Uma Maheswara Rao G
> Attachments: HDFS-8137-0.patch, HDFS-8137-1.patch
>
>
> Discussed with [~umamaheswararao] and [~vinayrpet], we should also send the
> EC schema to DataNode as well contained in the EC encoding/recovering
> command. The target DataNode will use it to guide the executing of the task.
> Another way would be, DataNode would just request schema actively thru a
> separate RPC call, and as an optimization consideration, DataNode may cache
> schemas to avoid repeatedly asking for the same schema twice.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
