I do get ActiveMQ supports data persistence (<http://activemq.apache.org/persistence.html>), but i cannot understand how to make it work, the result is when i restart ActiveMQ all the messages disappear, while queues and topics remain. 

I've read about to enable persistence on a database but i want to keep data on the filesystem since my system is facing database perfomance issues.

This is my activemq.xml

```
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this work for additional information regarding copyright ownership.
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distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<!-- START SNIPPET: example -->
<beans
  xmlns="http://www.springframework.org/schema/beans"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.springframework.org/schema/beans 
http://www.springframework.org/schema/beans/spring-beans.xsd
  http://activemq.apache.org/schema/core 
http://activemq.apache.org/schema/core/activemq-core.xsd">

<!-- Allows us to use system properties as variables in this configuration file -->
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="locations">
        <value>file:${activemq.conf}/credentials.properties</value>
    </property>
</bean>
<!-- Allows accessing the server log -->
<bean id="logQuery" class="io.fabric8.insight.log.log4j.Log4jLogQuery"
      lazy-init="false" scope="singleton"
      init-method="start" destroy-method="stop">
</bean>

<!--
    The <broker> element is used to configure the ActiveMQ broker.
-->
<broker xmlns="http://activemq.apache.org/schema/core" brokerName="localhost" dataDirectory="${activemq.data}">

    <destinationPolicy>
        <policyMap>
          <policyEntries>
            <policyEntry topic=">" >
                <!-- The constantPendingMessageLimitStrategy is used to prevent
                     slow topic consumers to block producers and affect other consumers
                     by limiting the number of messages that are retained
                     For more information, see:

                     http://activemq.apache.org/slow-consumer-handling.html

                -->
              <pendingMessageLimitStrategy>
                <constantPendingMessageLimitStrategy limit="1000"/>
              </pendingMessageLimitStrategy>
            </policyEntry>
          </policyEntries>
        </policyMap>
    </destinationPolicy>

    <!--
        The managementContext is used to configure how ActiveMQ is exposed in
        JMX. By default, ActiveMQ uses the MBean server that is started by
        the JVM. For more information, see:

        http://activemq.apache.org/jmx.html
    -->
    <managementContext>
        <managementContext createConnector="false"/>
    </managementContext>

    <!--
        Configure message persistence for the broker. The default persistence
        mechanism is the KahaDB store (identified by the kahaDB tag).
        For more information, see:

        http://activemq.apache.org/persistence.html
    -->
    <persistenceAdapter>
        <kahaDB directory="${activemq.data}/kahadb"/>
    </persistenceAdapter>

      <!--
        The systemUsage controls the maximum amount of space the broker will
        use before disabling caching and/or slowing down producers. For more information, see:
        http://activemq.apache.org/producer-flow-control.html
      -->
      <systemUsage>
        <systemUsage>
            <memoryUsage>
                <memoryUsage percentOfJvmHeap="70" />
            </memoryUsage>
            <storeUsage>
                <storeUsage limit="100 gb"/>
            </storeUsage>
            <tempUsage>
                <tempUsage limit="50 gb"/>
            </tempUsage>
        </systemUsage>
    </systemUsage>

    <!--
        The transport connectors expose ActiveMQ over a given protocol to
        clients and other brokers. For more information, see:

        http://activemq.apache.org/configuring-transports.html
    -->
    <transportConnectors>
        <!-- DOS protection, limit concurrent connections to 1000 and frame size to 100MB -->
        <transportConnector name="openwire" uri="tcp://0.0.0.0:61616?maximumConnections=1000&amp;wireFormat.maxFrameSize=104857600"/>
        <transportConnector name="amqp" uri="amqp://0.0.0.0:5672?maximumConnections=1000&amp;wireFormat.maxFrameSize=104857600"/>
        <transportConnector name="stomp" uri="stomp://0.0.0.0:61613?maximumConnections=1000&amp;wireFormat.maxFrameSize=104857600"/>
        <transportConnector name="mqtt" uri="mqtt://0.0.0.0:1883?maximumConnections=1000&amp;wireFormat.maxFrameSize=104857600"/>
        <transportConnector name="ws" uri="ws://0.0.0.0:61614?maximumConnections=1000&amp;wireFormat.maxFrameSize=104857600"/>
    </transportConnectors>

    <!-- destroy the spring context on shutdown to stop jetty -->
    <shutdownHooks>
        <bean xmlns="http://www.springframework.org/schema/beans" class="org.apache.activemq.hooks.SpringContextHook" />
    </shutdownHooks>

</broker>

<!--
    Enable web consoles, REST and Ajax APIs and demos
    The web consoles requires by default login, you can disable this in the jetty.xml file

    Take a look at ${ACTIVEMQ_HOME}/conf/jetty.xml for more details
-->
<import resource="jetty.xml"/>

```