[
https://issues.apache.org/jira/browse/HDFS-6186?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13979067#comment-13979067
]
Ming Ma commented on HDFS-6186:
-------------------------------
Cool.
What is the creation time of DatanodeStorageInfo, the first full block report
for that storage? Wonder if it can be set well before NN exit safemode and thus
the blocks will still be invalidated right after NN exit safemode; or we can
set larger TTL value to account for it.
Nit: In processFirstBlockReport, perhaps update the comment of "// If block
does not belong to any file, we are done.".
> Pause deletion of blocks when the namenode starts up
> ----------------------------------------------------
>
> Key: HDFS-6186
> URL: https://issues.apache.org/jira/browse/HDFS-6186
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: namenode
> Reporter: Suresh Srinivas
> Assignee: Jing Zhao
> Attachments: HDFS-6186.000.patch
>
>
> HDFS namenode can delete blocks very quickly, given the deletion happens as a
> parallel operation spread across many datanodes. One of the frequent
> anxieties I see is that a lot of data can be deleted very quickly, when a
> cluster is brought up, especially when one of the storage directories has
> failed and namenode metadata was copied from another storage. Copying wrong
> metadata would results in some of the newer files (if old metadata was
> copied) being deleted along with their blocks.
> HDFS-5986 now captures the number of pending deletion block on namenode webUI
> and JMX. I propose pausing deletion of blocks for a configured period of time
> (default 1 hour?) after namenode comes out of safemode. This will give enough
> time for the administrator to notice large number of pending deletion blocks
> and take corrective action.
> Thoughts?
--
This message was sent by Atlassian JIRA
(v6.2#6252)
