Setting up an AEM server from scratch - part 3

Configuring a Dispatcher Flush agent

Default agents are included with the installation. However, certain configuration is still needed and the same applies if you are defining a new agent:

• Open the Tools tab in AEM.

• Select Replication, then Agents on publish in the left panel.

• Double-click on the Dispatcher Flush item to open the overview.

• Click Edit - the Agent Settings dialog will open:

• In the Settings tab:

• Activate Enabled.
• Enter a Description.
• Leave the Serialization Type as Dispatcher Flush, or set it as such if creating a new agent.

• In the Transport tab, Enter the required URI for the new publish instance; for example:

• http://localhost:80/dispatcher/invalidate.cache.
• Enter the site-specific user account used for replication.
• You can configure other parameters as required.

For Dispatcher Flush agents, the URI property is used only if you use path-based virtual host entries to differentiate between farms, you use this field to target the  farm to invalidate. For example, farm #1 has a virtual host of www.mysite.com/path1/* and farm #2 has a virtual host of www.mysite.com/path2/*. You can use a URL of /path1/invalidate.cache to target the first farm and /path2/invalidate.cache to target the second farm.

Return to the Tools tab, from here you can Activate the Dispatcher Flush agent (Agents on publish).

The Dispatcher Flush replication agent is not active on author. You can access the same page in the publish environment by using the equivalent URI; for example, http://localhost:4503/etc/replication/agents.publish/flush.html.

And for the final bit on Replication: Monitoring!

• Access the Tools tab in AEM.

• Click Replication.

• Double-click the link to agents for the appropriate environment (either the left or the right pane); for example Agents on author.

• The resulting window shows an overview of all your replication agents for the author environment, including their target and status.

• Click the appropriate agent name (which is a link) to show detailed information on that agent:

• Here you can:

• See whether the agent is enabled.
• See the target of any replications.
• See whether the replication queue is currently active (enabled).
• See whether there are any items in the queue.
• Refresh or Clear to update the display of queue entries; this helps you see items enter and leave the queue.
• View Log to access the log of any actions by the replication agent.
• Test Connection to the target instance.
• Force Retry on any queue items if required.

CAUTION
Do not use the "Test Connection" link for the Reverse Replication Outbox on a publish instance.
If a replication test is performed for an Outbox queue, any items that are older than the test replication will be re-processed with every reverse replication.
If such items already exist in a queue, they can be found with the following XPath JCR query and should be removed. /jcr:root/var/replication/outbox//*[@cq:repActionType='TEST']


Source and for more info, please review: 
https://docs.adobe.com/docs/en/aem/6-2/deploy/configuring/replication.html

Ok, its time for some coffee.. when you are back, we will then setup the sling mappings on the publish server and also setup the Dispatcher.

See you in Part 4 :)