hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Maysam Yabandeh (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-6982) nntop: top­-like tool for name node users
Date Tue, 04 Nov 2014 19:35:35 GMT

    [ https://issues.apache.org/jira/browse/HDFS-6982?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14196664#comment-14196664
] 

Maysam Yabandeh commented on HDFS-6982:
---------------------------------------

Let me take an example. 
Time period: 60 seconds
Bucket duration: 20 seconds
Bucket/window = 3

Event1: time 00:10:55

Current time: 00:11:03
Current sum for the past window (1 min) = 1

Event2: time 00:11:54

Current time: 00:12:07
Current sum for the past window (1 min) = 1

Now for this behavior to be implemented correctly we need to zero the content of the bucket
number 3 because both Event1 and Event2 map to the same bucket but Event1 is irrelevant at
time 00:12:07 since it happened before the last 60 seconds.

Makes sense?


> nntop: top­-like tool for name node users
> -----------------------------------------
>
>                 Key: HDFS-6982
>                 URL: https://issues.apache.org/jira/browse/HDFS-6982
>             Project: Hadoop HDFS
>          Issue Type: New Feature
>            Reporter: Maysam Yabandeh
>            Assignee: Maysam Yabandeh
>         Attachments: HDFS-6982.patch, HDFS-6982.v2.patch, HDFS-6982.v3.patch, HDFS-6982.v4.patch,
HDFS-6982.v5.patch, HDFS-6982.v6.patch, nntop-design-v1.pdf
>
>
> In this jira we motivate the need for nntop, a tool that, similarly to what top does
in Linux, gives the list of top users of the HDFS name node and gives insight about which
users are sending majority of each traffic type to the name node. This information turns out
to be the most critical when the name node is under pressure and the HDFS admin needs to know
which user is hammering the name node and with what kind of requests. Here we present the
design of nntop which has been in production at Twitter in the past 10 months. nntop proved
to have low cpu overhead (< 2% in a cluster of 4K nodes), low memory footprint (less than
a few MB), and quite efficient for the write path (only two hash lookup for updating a metric).



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message