[
https://issues.apache.org/jira/browse/HDFS-6482?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14019111#comment-14019111
]
Colin Patrick McCabe commented on HDFS-6482:
--------------------------------------------
bq. * @param genStamp generation stamp of the blockFile dir =
Looks like a bad search-and-replace.
bq. public static File getDirectoryNoCreate(File root, long blockId) {
Maybe rather than having an {{IdBasedBlockDirectory}} class, we should just put
a static method like {{idToBlockDir}} inside {{DatanodeUtil}}, that simply
returns a {{File}}. Code that wants to call {{mkdir}} can always do it on its
own (with appropriate try/catch blocks.) I don't see a lot of value in having
a separate class, since the only interesting thing there is the {{File}}
contained inside.
I also don't like the side effect in the constructor. I guess we've done that
kind of thing in the past. But usually when we do that, there is a {{close}}
method that undoes the side-effect. In this case it just feels kind of
arbitrary... why should creating this object do a mkdir somewhere? You don't
need the object to use the directory, and you don't need to keep the object
around to keep the directory around.
bq. "The block ID of a block uniquely determines its position in the " +
"directory structure");
Should be "finalized block"
Looks good aside from that.
> 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: HDFS-6482.1.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)
