[jira] [Updated] (HADOOP-7714) Umbrella for usage of native calls to manage OS cache and readahead

["Sriram Rao (Updated) (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HADOOP-7714?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Sriram Rao updated HADOOP-7714:
-------------------------------

    Attachment: 7714-fallocate-20s.patch

Updated patch that calls posix_fallocate when creating a block on the datanode.
                
> Umbrella for usage of native calls to manage OS cache and readahead
> -------------------------------------------------------------------
>
>                 Key: HADOOP-7714
>                 URL: https://issues.apache.org/jira/browse/HADOOP-7714
>             Project: Hadoop Common
>          Issue Type: Bug
>          Components: io, native, performance
>    Affects Versions: 0.24.0
>            Reporter: Todd Lipcon
>            Assignee: Todd Lipcon
>         Attachments: 7714-fallocate-20s.patch, graphs.pdf, hadoop-7714-2.txt, hadoop-7714-20s-prelim.txt
>
>
> Especially in shared HBase/MR situations, management of the OS buffer cache is important. Currently, running a big MR job will evict all of HBase's hot data from cache, causing HBase performance to really suffer. However, caching of the MR input/output is rarely useful, since the datasets tend to be larger than cache and not re-read often enough that the cache is used. Having access to the native calls {{posix_fadvise}} and {{sync_data_range}} on platforms where they are supported would allow us to do a better job of managing this cache.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira