doc: merge repmgrd witness server description into failover section

doc/filelist.sgml

@@ -54,7 +54,6 @@
 <!ENTITY repmgrd-automatic-failover SYSTEM "repmgrd-automatic-failover.sgml">
 <!ENTITY repmgrd-configuration SYSTEM "repmgrd-configuration.sgml">
 <!ENTITY repmgrd-operation SYSTEM "repmgrd-operation.sgml">
-<!ENTITY repmgrd-witness-server SYSTEM "repmgrd-witness-server.sgml">
 <!ENTITY repmgrd-bdr SYSTEM "repmgrd-bdr.sgml">
 
 <!ENTITY repmgr-primary-register SYSTEM "repmgr-primary-register.sgml">

doc/repmgr.sgml

@@ -84,7 +84,6 @@
   &repmgrd-automatic-failover;
   &repmgrd-configuration;
   &repmgrd-operation;
-  &repmgrd-witness-server;
   &repmgrd-bdr;
  </part>
 

doc/repmgrd-automatic-failover.sgml

@@ -13,36 +13,45 @@
   providing monitoring information about the state of each standby.
  </para>
 
-  <sect1 id="cascading-replication">
+<sect1 id="repmgrd-witness-server" xreflabel="Using a witness server with repmgrd">
  <indexterm>
    <primary>repmgrd</primary>
-   <secondary>cascading replication</secondary>
+   <secondary>witness server</secondary>
  </indexterm>
 
  <indexterm>
-   <primary>cascading replication</primary>
+   <primary>witness server</primary>
    <secondary>repmgrd</secondary>
  </indexterm>
 
- <title>repmgrd and cascading replication</title>
+ <title>Using a witness server with repmgrd</title>
  <para>
-  Cascading replication - where a standby can connect to an upstream node and not
+   In a situation caused e.g. by a network interruption between two
-  the primary server itself - was introduced in PostgreSQL 9.2. &repmgr; and
+   data centres, it's important to avoid a "split-brain" situation where
-  <application>repmgrd</application> support cascading replication by keeping track of the relationship
+   both sides of the network assume they are the active segment and the
-  between standby servers - each node record is stored with the node id of its
+   side without an active primary unilaterally promotes one of its standbys.
-  upstream ("parent") server (except of course the primary server).
  </para>
  <para>
-  In a failover situation where the primary node fails and a top-level standby
+   To prevent this situation happening, it's essential to ensure that one
-  is promoted, a standby connected to another standby will not be affected
+   network segment has a "voting majority", so other segments will know
-  and continue working as normal (even if the upstream standby it's connected
+   they're in the minority and not attempt to promote a new primary. Where
-  to becomes the primary node). If however the node's direct upstream fails,
+   an odd number of servers exists, this is not an issue. However, if each
-  the &quot;cascaded standby&quot; will attempt to reconnect to that node's parent
+   network has an even number of nodes, it's necessary to provide some way
-  (unless <varname>failover</varname> is set to <literal>manual</literal> in
+   of ensuring a majority, which is where the witness server becomes useful.
-  <filename>repmgr.conf</filename>).
+ </para>
+ <para>
+   This is not a fully-fledged standby node and is not integrated into
+   replication, but it effectively represents the "casting vote" when
+   deciding which network segment has a majority. A witness server can
+   be set up using <xref linkend="repmgr-witness-register">. Note that it only
+   makes sense to create a witness server in conjunction with running
+   <application>repmgrd</application>; the witness server will require its own
+   <application>repmgrd</application> instance.
  </para>
 
-  </sect1>
+</sect1>
+
+
 <sect1 id="repmgrd-network-split" xreflabel="Handling network splits with repmgrd">
  <indexterm>
    <primary>repmgrd</primary>
@@ -96,4 +105,36 @@
 </sect1>
 
 
+  <sect1 id="cascading-replication">
+ <indexterm>
+   <primary>repmgrd</primary>
+   <secondary>cascading replication</secondary>
+ </indexterm>
+
+ <indexterm>
+   <primary>cascading replication</primary>
+   <secondary>repmgrd</secondary>
+ </indexterm>
+
+ <title>repmgrd and cascading replication</title>
+ <para>
+  Cascading replication - where a standby can connect to an upstream node and not
+  the primary server itself - was introduced in PostgreSQL 9.2. &repmgr; and
+  <application>repmgrd</application> support cascading replication by keeping track of the relationship
+  between standby servers - each node record is stored with the node id of its
+  upstream ("parent") server (except of course the primary server).
+ </para>
+ <para>
+  In a failover situation where the primary node fails and a top-level standby
+  is promoted, a standby connected to another standby will not be affected
+  and continue working as normal (even if the upstream standby it's connected
+  to becomes the primary node). If however the node's direct upstream fails,
+  the &quot;cascaded standby&quot; will attempt to reconnect to that node's parent
+  (unless <varname>failover</varname> is set to <literal>manual</literal> in
+  <filename>repmgr.conf</filename>).
+ </para>
+
+  </sect1>
+
+
 </chapter>

doc/repmgrd-witness-server.sgml

@@ -1,31 +0,0 @@
-<chapter id="repmgrd-witness-server" xreflabel="Using a witness server with repmgrd">
- <indexterm>
-   <primary>repmgrd</primary>
-   <secondary>witness server</secondary>
- </indexterm>
-
- <title>Using a witness server with repmgrd</title>
- <para>
-   In a situation caused e.g. by a network interruption between two
-   data centres, it's important to avoid a "split-brain" situation where
-   both sides of the network assume they are the active segment and the
-   side without an active primary unilaterally promotes one of its standbys.
- </para>
- <para>
-   To prevent this situation happening, it's essential to ensure that one
-   network segment has a "voting majority", so other segments will know
-   they're in the minority and not attempt to promote a new primary. Where
-   an odd number of servers exists, this is not an issue. However, if each
-   network has an even number of nodes, it's necessary to provide some way
-   of ensuring a majority, which is where the witness server becomes useful.
- </para>
- <para>
-   This is not a fully-fledged standby node and is not integrated into
-   replication, but it effectively represents the "casting vote" when
-   deciding which network segment has a majority. A witness server can
-   be set up using <xref linkend="repmgr-witness-register">. Note that it only
-   makes sense to create a witness server in conjunction with running
-   <application>repmgrd</application>; the witness server will require its own
-   <application>repmgrd</application> instance.
- </para>
-</chapter>