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From "Keys Botzum (JIRA)" <j...@apache.org>
Subject [jira] [Created] (ACCUMULO-1493) documentation clarification regarding dependencies
Date Tue, 04 Jun 2013 18:11:22 GMT
Keys Botzum created ACCUMULO-1493:
-------------------------------------

             Summary: documentation clarification regarding dependencies
                 Key: ACCUMULO-1493
                 URL: https://issues.apache.org/jira/browse/ACCUMULO-1493
             Project: Accumulo
          Issue Type: Bug
          Components: docs
    Affects Versions: 1.5.1
         Environment: MapR 2.1.1
            Reporter: Keys Botzum
            Priority: Minor


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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