[
https://issues.apache.org/jira/browse/HDFS-8873?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Daniel Templeton updated HDFS-8873:
-----------------------------------
Attachment: HDFS-8873.003.patch
New patch. [~cmccabe], I addressed your concerns about key name, whitespace,
and comments. I haven't done anything in the patch that will stand in the way
of someone extending the throttle concept to be more flexible later, but I
don't think it's worth the effort to proactively invest in doing more to enable
that extension since it may well never happen.
> throttle directoryScanner
> -------------------------
>
> Key: HDFS-8873
> URL: https://issues.apache.org/jira/browse/HDFS-8873
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: datanode
> Affects Versions: 2.7.1
> Reporter: Nathan Roberts
> Assignee: Daniel Templeton
> Attachments: HDFS-8873.001.patch, HDFS-8873.002.patch,
> HDFS-8873.003.patch
>
>
> The new 2-level directory layout can make directory scans expensive in terms
> of disk seeks (see HDFS-8791) for details.
> It would be good if the directoryScanner() had a configurable duty cycle that
> would reduce its impact on disk performance (much like the approach in
> HDFS-8617).
> Without such a throttle, disks can go 100% busy for many minutes at a time
> (assuming the common case of all inodes in cache but no directory blocks
> cached, 64K seeks are required for full directory listing which translates to
> 655 seconds)
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
