hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Hudson (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-7217) Documentation: Update section 11.5.1 to recommend that hbase.regionserver.checksum.verify is set
Date Tue, 27 Nov 2012 00:00:59 GMT

    [ https://issues.apache.org/jira/browse/HBASE-7217?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13504250#comment-13504250
] 

Hudson commented on HBASE-7217:
-------------------------------

Integrated in HBase-TRUNK-on-Hadoop-2.0.0 #274 (See [https://builds.apache.org/job/HBase-TRUNK-on-Hadoop-2.0.0/274/])
    HBASE-7217 Documentation: Update section 11.5.1 to recommend that hbase.regionserver.checksum.verify
is set (Revision 1413793)

     Result = FAILURE
stack : 
Files : 
* /hbase/trunk/src/docbkx/performance.xml

                
> Documentation: Update section 11.5.1 to recommend that hbase.regionserver.checksum.verify
is set
> ------------------------------------------------------------------------------------------------
>
>                 Key: HBASE-7217
>                 URL: https://issues.apache.org/jira/browse/HBASE-7217
>             Project: HBase
>          Issue Type: Improvement
>          Components: documentation
>    Affects Versions: 0.94.2
>            Reporter: Neil Ferguson
>            Priority: Minor
>             Fix For: 0.96.0
>
>         Attachments: 7217.txt
>
>
> When short-circuit reads are enabled (dfs.client.read.shortcircuit = true), reading with
checksums enabled (dfs.client.read.shortcircuit.skip.checksum = false) follows a completely
different, and much slower, path to reading with checksums disabled (BlockReaderLocal uses
something called a "slow buffer", which is, unsurprisingly, slow). My tests show that this
path is actually slower than having short-circuit reads disabled.
> Therefore, I think section 11.5.1 of the HBase documentation should recommend that hbase.regionserver.checksum.verify
be set to true when using short-circuit reads. I'd suggest the following:
> "For optimal performance when short-circuit reads are enabled, it is recommended that
HDFS checksums are disabled. To maintain data integrity with HDFS checksums disabled, HBase
can be configured to write its own checksums into its datablocks and verify against these.
See Section 11.4.9. "hbase.regionserver.checksum.verify".

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira

Mime
View raw message