[jira] [Commented] (HADOOP-10120) Additional sliding window metrics

["Steve Loughran (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-10120?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13828652#comment-13828652 ] 

Steve Loughran commented on HADOOP-10120:
-----------------------------------------

Some general moving average classes would be convenient for a lot of things.

For stats collection on openstack HTTP operations I added one to calculate the ongoing mean & variance: https://github.com/apache/hadoop-common/blob/trunk/hadoop-tools/hadoop-openstack/src/main/java/org/apache/hadoop/fs/swift/util/DurationStats.java

For Hoya I'm doing something more complicated where I want some kind of half-life on failure rates, to assess the reliability of nodes in the cluster -for long-lived clusters cumulative counts are the wrong approach.  All long-lived YARN services are going to need this

> Additional sliding window metrics
> ---------------------------------
>
>                 Key: HADOOP-10120
>                 URL: https://issues.apache.org/jira/browse/HADOOP-10120
>             Project: Hadoop Common
>          Issue Type: New Feature
>          Components: metrics
>    Affects Versions: 2.2.0
>            Reporter: Andrew Wang
>            Assignee: Andrew Wang
>
> For HDFS-5350 we'd like to report the last few fsimage transfer times as a health metric. This would mean (for example) a sliding window of the last 10 transfer times, when it was last updated, the total count. It'd be nice to have a metrics class that did this.
> It'd also be interesting to have some kind of time-based sliding window for statistics like counts and averages. This would let us answer questions like "how many RPCs happened in the last 10s? minute? 5 minutes? 10 minutes?". Commutative metrics like counts and averages are easy to aggregate in this fashion.



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