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From "Josh Elser (JIRA)" <>
Subject [jira] [Commented] (ACCUMULO-1493) documentation clarification for MapR
Date Tue, 07 Jan 2014 23:49:50 GMT


Josh Elser commented on ACCUMULO-1493:

[~kbotzum], are you planning on submitting a patch for this that could be included in 1.6.0?
I'm trying to weed out tickets that aren't going to be done for 1.6.0.

> documentation clarification for MapR
> ------------------------------------
>                 Key: ACCUMULO-1493
>                 URL:
>             Project: Accumulo
>          Issue Type: Improvement
>          Components: docs
>    Affects Versions: 1.5.0
>         Environment: MapR 2.1.1
>            Reporter: Keys Botzum
>            Priority: Minor
>              Labels: Documentation
>             Fix For: 1.5.1, 1.6.0
> When testing Accumulo with MapR we encountered a few minor issues that should be addressable
via documentation. They are:
> 1)  Accumulo 1.5 requires these jar files:
>                  commons-configuration-1.6.jar
>                  commons-collections-3.2.1.jar
>                  commons-io-2.1.jar
> They are not part of the MapR distribution and do not appear to be part of the standard
Hadoop distribution either. These dependencies should be documented.
> 2) MapR has the requirement that the block/chunk size be a multiple of 64K. As a result
the default Accumulo algorithm for defining the WAL block size does not work with MapR. This
should be documented. In more detail...
>      By default, the property tserver.wal.blocksize is 0, in which case Accumlo sets
it to 1.1 * tserver.walog.max.size, which defaults to 512M. This results in a MapR chunksize
that is not a multiple of 64k, which means any writes to the WAL will fail.  So in accumulo-site.xml,
set tserver.wal.blocksize to a multiple of 64K (such as 562M, which is about 1.1 times  the
WAL max.  Insert these lines:
>            <property>
>             <name>tserver.wal.blocksize</name>
>             <value>562M</value>
>            </property>
> 3) Need to document the Accumulo log sync mechanism for MapR. Accumulo 1.5 changed the
way the WAL is sync'ed and now uses the distributed file system.    A filesystem-specific
property is needed to specify the class for MapR. Add this to accumulo-site.xml:
>            <property>
>              <name>master.walog.closer.implementation</name>
>        <value>org.apache.accumulo.server.master.recovery.MapRLogCloser</value>
>            </property>

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