HBASE-3500 Documentation update for replication

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1067598 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -45,6 +45,7 @@ Release 0.91.0 - Unreleased
    HBASE-3502  Can't open region because can't open .regioninfo because
                AlreadyBeingCreatedException
    HBASE-3501  Remove the deletion limit in LogCleaner
+   HBASE-3500  Documentation update for replicatio
 
 
   IMPROVEMENTS

src/main/javadoc/org/apache/hadoop/hbase/replication/package.html

@@ -92,6 +92,7 @@ to another.
   <name>hbase.replication</name>
   <value>true</value>
 &lt;/property&gt;</pre>
+      deploy the files, and then restart HBase if it was running.
     </li>
     <li>Run the following command in the master's shell while it's running
     <pre>add_peer</pre>
@@ -100,6 +101,18 @@ to another.
     to use a different <b>zookeeper.znode.parent</b> since they can't
     write in the same folder.
     </li>
+    <li>
+    Once you have a peer, you need to enable replication on your column families.
+    One way to do it is to alter the table and to set the scope like this:
+    <pre>
+      disable 'your_table'
+      alter 'your_table', {NAME => 'family_name', REPLICATION_SCOPE => '1'}
+      enable 'your_table'
+    </pre>
+    Currently, a scope of 0 (default) means that it won't be replicated and a
+    scope of 1 means it's going to be. In the future, different scope can be
+    used for routing policies.
+    </li>
 </ol>
 
 You can confirm that your setup works by looking at any region server's log

src/site/xdoc/replication.xml

@@ -43,7 +43,10 @@
         other well known solutions like MySQL master/slave replication where
         there’s only one bin log to keep track of. One master cluster can
         replicate to any number of slave clusters, and each region server will
-        participate to replicate their own stream of edits.
+        participate to replicate their own stream of edits. For more information
+        on the different properties of master/slave replication and other types
+        of replication, please consult <a href="http://highscalability.com/blog/2009/8/24/how-google-serves-data-from-multiple-datacenters.html">
+        How Google Serves Data From Multiple Datacenters</a>.
       </p>
       <p>
         The replication is done asynchronously, meaning that the clusters can
@@ -73,6 +76,17 @@
       </p>
       <img src="images/replication_overview.png"/>
     </section>
+    <section name="Enabling replication">
+      <p>
+        The guide on enabling and using cluster replication is contained
+        in the API documentation shipped with your HBase distribution.
+      </p>
+      <p>
+        The most up-to-date documentation is
+        <a href="apidocs/org/apache/hadoop/hbase/replication/package-summary.html#requirements">
+        available at this address</a>.
+      </p>
+    </section>
     <section name="Life of a log edit">
       <p>
         The following sections describe the life of a single edit going from a
@@ -350,15 +364,6 @@
       </section>
     </section>
     <section name="FAQ">
-      <section name="Why do all clusters need to be in the same timezone?">
-        <p>
-          Suppose an edit to cell X happens in a EST cluster, then 2 minutes
-          later a new edits happens to the same cell in a PST cluster and that
-          both clusters are in a master-master replication. The second edit is
-          considered younger, so the first will always hide it while in fact the
-          second is older.
-        </p>
-      </section>
       <section name="GLOBAL means replicate? Any provision to replicate only to cluster X and not to cluster Y? or is that for later?">
         <p>
           Yes, this is for much later.