doc/book/src/java-broker/Java-Broker-Concepts-Virtual-Hosts.xml

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<section id="Java-Broker-Concepts-Virtual-Hosts">
<title>Virtual Hosts</title>
<para>A Broker has one or more <emphasis>Virtual Host</emphasis>s. Each <emphasis>Virtual Host</emphasis>
has an independant namespace for its collection of <emphasis>Exchanges</emphasis>, <emphasis>Queues</emphasis>,
and associated objects. Client <emphasis>Connection</emphasis>s are made a specific <emphasis>Virtual Host</emphasis>,
with one being configured as the default for clients that can't or don't specify which they wish to connect to.
</para>
<para>
    The following diagram depicts the Virtual Host model:
    <figure>
        <title>Virtual Host Model</title>
        <mediaobject>
          <imageobject>
            <imagedata fileref="images/VirtualHost-Model.png" format="PNG" scalefit="1"/>
          </imageobject>
          <textobject>
            <phrase>Virtual Host Model</phrase>
          </textobject>
        </mediaobject>
    </figure>
</para>
<para>Each <emphasis>Virtual Host</emphasis> has its own <emphasis>Message Store</emphasis> which is used to store persistent
messages on durable <emphasis>Queues</emphasis> it contains, as well as the configuration of any durable
<emphasis>Queues</emphasis>, <emphasis>Exchanges</emphasis>, and <emphasis>Bindings</emphasis> made during its operation.</para>
<para>
  The Java Broker supports different types of <emphasis>Virtual Host</emphasis>, which providing
  for different High Availability patterns.  The <emphasis>standard</emphasis> <emphasis>Virtual
  Host</emphasis> type provides no replication and is designed for standalone environments. It
  supports a number of different <emphasis>Message Store</emphasis> implementations:
    <itemizedlist>
        <listitem><para><link linkend="Java-Broker-Stores-SQL-Store">JDBC Message Store</link></para></listitem>
        <listitem><para><link linkend="Java-Broker-Stores-Derby-Store">Derby Message Store</link></para></listitem>
        <listitem><para><link linkend="Java-Broker-Stores-BDB-Store">Berkeley DB Message Store</link></para></listitem>
        <listitem><para><link linkend="Java-Broker-Stores-Memory-Store">Memory Message Store</link></para></listitem>
     </itemizedlist>
</para>
<para>
  The <emphasis>BDB_HA</emphasis> <emphasis>Virtual Host</emphasis> provides clustering for
  reliability using the HA capabilties of the Oracle Berkeley DB (Java Edition) (see
  <link linkend="Java-Broker-Stores-HA-BDB-Store">Berkeley DB HA Message Store</link>).
</para>
<para>Virtual Hosts configuration is covered in <xref linkend="Java-Broker-Virtual-Hosts"/>.</para>
</section>