hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Tsz Wo (Nicholas), SZE (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HDFS-1114) Reducing NameNode memory usage by an alternate hash table
Date Thu, 01 Jul 2010 18:23:53 GMT

    [ https://issues.apache.org/jira/browse/HDFS-1114?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12884372#action_12884372
] 

Tsz Wo (Nicholas), SZE commented on HDFS-1114:
----------------------------------------------

Ravi has done some performance analysis on Yahoo! production cluster fs image.

46400490 files & directories , 70074790 blocks = 116475280
FsImage Disk size - 7.5GB. 

| || heap size at NN startup || fsimage loading time |
| Without the patch | 19.64 GB | 603 s |
| With the patch | 17.03 GB | 577 s|
| % improvement | 13.2% | 4.3%|

Thanks Ravi!

> Reducing NameNode memory usage by an alternate hash table
> ---------------------------------------------------------
>
>                 Key: HDFS-1114
>                 URL: https://issues.apache.org/jira/browse/HDFS-1114
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: name-node
>            Reporter: Tsz Wo (Nicholas), SZE
>            Assignee: Tsz Wo (Nicholas), SZE
>             Fix For: 0.22.0
>
>         Attachments: benchmark20100618.patch, GSet20100525.pdf, gset20100608.pdf, h1114_20100607.patch,
h1114_20100614b.patch, h1114_20100615.patch, h1114_20100616b.patch, h1114_20100617.patch,
h1114_20100617b.patch, h1114_20100617b2_y0.20.1xx.patch, h1114_20100617b_y0.20.1xx.patch
>
>
> NameNode uses a java.util.HashMap to store BlockInfo objects.  When there are many blocks
in HDFS, this map uses a lot of memory in the NameNode.  We may optimize the memory usage
by a light weight hash table implementation.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message