You are viewing a plain text version of this content. The canonical link for it is here.

Posted to hdfs-issues@hadoop.apache.org by "Xiaoyu Yao (JIRA)" <ji...@apache.org> on 2014/10/27 01:22:33 UTC

[jira] [Updated] (HDFS-7291) Persist in-memory replicas using unbuffered IO should only applies to supported Linux version

     [ https://issues.apache.org/jira/browse/HDFS-7291?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Xiaoyu Yao updated HDFS-7291:
-----------------------------
    Attachment: HDFS-7291.0.patch

Attach the initial patch that checks the Linux version string returned from POSIX 'uname -r' command.

> Persist in-memory replicas using unbuffered IO should only applies to supported Linux version
> ---------------------------------------------------------------------------------------------
>
>                 Key: HDFS-7291
>                 URL: https://issues.apache.org/jira/browse/HDFS-7291
>             Project: Hadoop HDFS
>          Issue Type: Sub-task
>          Components: datanode
>    Affects Versions: 2.6.0
>            Reporter: Xiaoyu Yao
>            Assignee: Xiaoyu Yao
>             Fix For: 2.6.0
>
>         Attachments: HDFS-7291.0.patch
>
>
> HDFS-7090 changes to persist in-memory replicas using unbuffered IO on Linux and Windows. On Linux distribution, it relies on the sendfile() API between two file descriptors to achieve unbuffered IO copy. According to Linux document at http://man7.org/linux/man-pages/man2/sendfile.2.html, this is only supported on Linux kernel 2.6.33+.  This JIRA is to limit the usage of sendfile() for lazy persist only on Linux distribution with kernel version higher than 2.6.33. For unsupported version, lazy persist will fallback to normal buffered IO.



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