[
https://issues.apache.org/jira/browse/HDFS-395?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13070200#comment-13070200
]
Suresh Srinivas commented on HDFS-395:
--------------------------------------
Just noticed that the attached patch explicitDeleteAcks.patch is different from
Diff: https://reviews.apache.org/r/998/diff
For 988/diff, additional comments:
# Are you not planning to rename the block file to be deleted? This is done in
explicitDeleteAcks.patch
# Ignore comment 1. in my previous comment. I do not understand
ReceivedDeletedBlockInfo#WILDCARD_HINT is being used.
> DFS Scalability: Incremental block reports
> ------------------------------------------
>
> Key: HDFS-395
> URL: https://issues.apache.org/jira/browse/HDFS-395
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: dhruba borthakur
> Assignee: Tomasz Nykiel
> Attachments: blockReportPeriod.patch, explicitDeleteAcks.patch
>
>
> I have a cluster that has 1800 datanodes. Each datanode has around 50000
> blocks and sends a block report to the namenode once every hour. This means
> that the namenode processes a block report once every 2 seconds. Each block
> report contains all blocks that the datanode currently hosts. This makes the
> namenode compare a huge number of blocks that practically remains the same
> between two consecutive reports. This wastes CPU on the namenode.
> The problem becomes worse when the number of datanodes increases.
> One proposal is to make succeeding block reports (after a successful send of
> a full block report) be incremental. This will make the namenode process only
> those blocks that were added/deleted in the last period.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
