Add pointer to Aaron blog on ulimit. Add note to hregionpartitioner about it not being suitable for incremental bulk load

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1036378 13f79535-47bb-0310-9956-ffa450edef68

src/docbkx/book.xml

@@ -336,6 +336,11 @@ Usually you'll want to use the latest version available except the problematic u
       will up the file descriptors for a user but for whatever reason,
       HBase is running as some other users.  HBase prints in its logs
       as the first line the ulimit its seeing.  Ensure its whats expected.
+    <footnote>
+    <para>A useful read setting config on you hadoop cluster isAaron Kimballs'
+    <link xlink:ref="http://www.cloudera.com/blog/2009/03/configuration-parameters-what-can-you-just-ignore/">Configuration Parameters: What can you just ignore?</link>
+    </para>
+    </footnote>
       </para>
         <section xml:id="ulimit_ubuntu">
           <title><varname>ulimit</varname> on Ubuntu</title>

src/main/java/org/apache/hadoop/hbase/mapreduce/HRegionPartitioner.java

@@ -36,6 +36,11 @@ import org.apache.hadoop.mapreduce.Partitioner;
  * Keys are grouped according to the regions that currently exist
  * so that each reducer fills a single region so load is distributed.
  *
+ * <p>This class is not suitable as partitioner creating hfiles
+ * for incremental bulk loads as region spread will likely change between time of
+ * hfile creation and load time. See {@link LoadIncrementalHFiles}
+ * and <a href="http://hbase.apache.org/docs/current/bulk-loads.html">Bulk Load</a>.
+ *
  * @param <KEY>  The type of the key.
  * @param <VALUE>  The type of the value.
  */