[
https://issues.apache.org/jira/browse/HDFS-14313?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16900563#comment-16900563
]
Lisheng Sun commented on HDFS-14313:
------------------------------------
Thank [~jojochuang] for your suggestion.
{quote}One thing that's missing out in the v11 is the update to
hdfs-default.xml which was missing since v8.
{quote}
According to [~linyiqun] suggetion, I define a hard-coded threadold time value
like 1000ms in ReplicaCachingGetSpaceUsed. So remove config in hdfs-default.xml.
{code:java}
private static final long DEEP_COPY_REPLICA_THRESHOLD_MS = 50;
private static final long REPLICA_CACHING_GET_SPACE_USED_THRESHOLD_MS = 1000;
{code}
{quote}
Additionally there should be an additional config key
"fs.getspaceused.classname" in core-default.xml, and state that possible
options are
org.apache.hadoop.fs.DU (default)
org.apache.hadoop.fs.WindowsGetSpaceUsed
org.apache.hadoop.fs.DFCachingGetSpaceUsed
org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.ReplicaCachingGetSpaceUsed
{quote}
That ReplicaCachingGetSpaceUsed of hdfs module is added in core-default.xml of
common module should not be very good. Please correct me if I was wrong. Thank
you again.
> Get hdfs used space from FsDatasetImpl#volumeMap#ReplicaInfo in memory
> instead of df/du
> ----------------------------------------------------------------------------------------
>
> Key: HDFS-14313
> URL: https://issues.apache.org/jira/browse/HDFS-14313
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: datanode, performance
> Affects Versions: 2.6.0, 2.7.0, 2.8.0, 2.9.0, 3.0.0, 3.1.0
> Reporter: Lisheng Sun
> Assignee: Lisheng Sun
> Priority: Major
> Attachments: HDFS-14313.000.patch, HDFS-14313.001.patch,
> HDFS-14313.002.patch, HDFS-14313.003.patch, HDFS-14313.004.patch,
> HDFS-14313.005.patch, HDFS-14313.006.patch, HDFS-14313.007.patch,
> HDFS-14313.008.patch, HDFS-14313.009.patch, HDFS-14313.010.patch,
> HDFS-14313.011.patch
>
>
> There are two ways of DU/DF getting used space that are insufficient.
> # Running DU across lots of disks is very expensive and running all of the
> processes at the same time creates a noticeable IO spike.
> # Running DF is inaccurate when the disk sharing by multiple datanode or
> other servers.
> Getting hdfs used space from FsDatasetImpl#volumeMap#ReplicaInfos in memory
> is very small and accurate.
--
This message was sent by Atlassian JIRA
(v7.6.14#76016)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
