[
https://issues.apache.org/jira/browse/HDFS-6482?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14055173#comment-14055173
]
James Thomas commented on HDFS-6482:
------------------------------------
[~sureshms] Thanks for the info. I don't understand your last comment -- could
you explain further? Also, I don't think it makes sense to support both the
LDir structure and this structure simultaneously. We would need to continue to
maintain information in the ReplicaMap about where each block was located
(since we wouldn't know whether it was stored with the old or new scheme), so
there would be no memory usage savings. I'm not sure we would ever reach a
point where all blocks stored with the old scheme would be gone and we could
officially stop using the location field in ReplicaInfo.
> Use block ID-based block layout on datanodes
> --------------------------------------------
>
> Key: HDFS-6482
> URL: https://issues.apache.org/jira/browse/HDFS-6482
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: datanode
> Affects Versions: 2.5.0
> Reporter: James Thomas
> Assignee: James Thomas
> Attachments: 6482-design.doc, HDFS-6482.1.patch, HDFS-6482.2.patch,
> HDFS-6482.3.patch, HDFS-6482.4.patch, HDFS-6482.5.patch, HDFS-6482.6.patch,
> HDFS-6482.7.patch, HDFS-6482.patch
>
>
> Right now blocks are placed into directories that are split into many
> subdirectories when capacity is reached. Instead we can use a block's ID to
> determine the path it should go in. This eliminates the need for the LDir
> data structure that facilitates the splitting of directories when they reach
> capacity as well as fields in ReplicaInfo that keep track of a replica's
> location.
> An extension of the work in HDFS-3290.
--
This message was sent by Atlassian JIRA
(v6.2#6252)
