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From dm...@apache.org
Subject svn commit: r1170819 - /hbase/trunk/src/docbkx/book.xml
Date Wed, 14 Sep 2011 19:55:57 GMT
Author: dmeil
Date: Wed Sep 14 19:55:57 2011
New Revision: 1170819

URL: http://svn.apache.org/viewvc?rev=1170819&view=rev
Log:
HBASE-4408.  book.xml, faq

Modified:
    hbase/trunk/src/docbkx/book.xml

Modified: hbase/trunk/src/docbkx/book.xml
URL: http://svn.apache.org/viewvc/hbase/trunk/src/docbkx/book.xml?rev=1170819&r1=1170818&r2=1170819&view=diff
==============================================================================
--- hbase/trunk/src/docbkx/book.xml (original)
+++ hbase/trunk/src/docbkx/book.xml Wed Sep 14 19:55:57 2011
@@ -1703,6 +1703,23 @@ hbase> describe 't1'</programlisting>
     <qandaset defaultlabel='faq'>
         <qandadiv><title>General</title>
         <qandaentry>
+                <question><para>When should I use HBase?</para></question>
+            <answer>
+                <para>
+              Anybody can download and give HBase a spin, even on a laptop.  The scope of
this answer is when 
+              would it be best to use HBase in a <emphasis>real</emphasis> deployment.
+                </para>
+                <para>First, make sure you have enough hardware.  Even HDFS doesn't
do well with anything less than
+                5 DataNodes (due to things such as HDFS block replication which has a default
of 3), plus a NameNode.
+                Second, make sure you have enough data.  HBase isn't suitable for every problem.
 If you have 
+                hundreds of millions or billions of rows, then HBase is a good candidate.
 If you only have a few 
+                thousand/million rows, then using a traditional RDBMS might be a better choice
due to the 
+                fact that all of your data might wind up on a single node (or two) and the
rest of the cluster may
+                be sitting idle.
+                </para>
+            </answer>
+        </qandaentry>
+        <qandaentry>
                 <question><para>Are there other HBase FAQs?</para></question>
             <answer>
                 <para>
@@ -1738,18 +1755,6 @@ hbase> describe 't1'</programlisting>
                 </para>
             </answer>
         </qandaentry>
-        <qandaentry xml:id="brand.new.compressor">
-            <question><para>Why are logs flooded with '2011-01-10 12:40:48,407
INFO org.apache.hadoop.io.compress.CodecPool: Got
-            brand-new compressor' messages?</para></question>
-            <answer>
-                <para>
-                    Because we are not using the native versions of compression
-                    libraries.  See <link xlink:href="https://issues.apache.org/jira/browse/HBASE-1900">HBASE-1900
Put back native support when hadoop 0.21 is released</link>.
-                    Copy the native libs from hadoop under hbase lib dir or
-                    symlink them into place and the message should go away.
-                </para>
-            </answer>
-        </qandaentry>
     </qandadiv>
     <qandadiv xml:id="ec2"><title>EC2</title>
         <qandaentry>
@@ -1796,6 +1801,18 @@ When I build, why do I always get <code>
                 </para>
             </answer>
         </qandaentry>
+        <qandaentry xml:id="brand.new.compressor">
+            <question><para>Why are logs flooded with '2011-01-10 12:40:48,407
INFO org.apache.hadoop.io.compress.CodecPool: Got
+            brand-new compressor' messages?</para></question>
+            <answer>
+                <para>
+                    Because we are not using the native versions of compression
+                    libraries.  See <link xlink:href="https://issues.apache.org/jira/browse/HBASE-1900">HBASE-1900
Put back native support when hadoop 0.21 is released</link>.
+                    Copy the native libs from hadoop under hbase lib dir or
+                    symlink them into place and the message should go away.
+                </para>
+            </answer>
+        </qandaentry>
     </qandadiv>
     <qandadiv><title>How do I...?</title>
         <qandaentry xml:id="secondary.indices">



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