accumulo-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Todd Lipcon (JIRA)" <>
Subject [jira] [Commented] (ACCUMULO-140) Prevent linux from caching write ahead log files
Date Wed, 09 May 2012 16:49:49 GMT


Todd Lipcon commented on ACCUMULO-140:

HDFS uses fadvise(DONT_NEED) in addition to sync_file_range to trigger early writeback. sync_file_range
has a flag to enqueue for writeback without forcing a true fsync, which is nicer on the rest
of the system (eg doesn't force a journal fsync like a normal fsync() does). Check out
in trunk DFS.
> Prevent linux from caching write ahead log files
> ------------------------------------------------
>                 Key: ACCUMULO-140
>                 URL:
>             Project: Accumulo
>          Issue Type: Improvement
>          Components: logger
>            Reporter: Keith Turner
>            Assignee: Eric Newton
>             Fix For: 1.5.0
> While at ApacheCon I attended a talk about Cassandra.  The developer mentioned using
posix_fadvise to prevent linux from storing edit/write ahead log data in the page cache. 
This sounds great.  Accumulo can do this for its write ahead logs.
> Using posix_fadvise was also mentioned for compactions, this is something Accumulo can
not do because its compactions read and write to hdfs.

This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:!default.jspa
For more information on JIRA, see:


View raw message