Does replicated data pass directly between SPIAgents

The flow of data in a synchronization using the SPIAgent Add-on depends on the configuration options defined for the job. By default, the data is transfered through the main SureSync installation. For example, assume you have ServerA with the full SureSync application installed. In this example, the machine does not host any of the data being synchronized. The machine only controls the synchronization. The SPIAgent is installed on ServerB and ServerC. The data is being synchronized between ServerB and ServerC. In this scenario, the data being synchronized will be passed through the ServerA machine. This default configuration eliminates potential firewall issues between the ServerB and ServerC machines but does result in additional bandwidth transmission.

Two methods are available to address this issue. First, using the default options and installing SureSync on either ServerB or ServerC will prevent the additional transfer. This happens because the data is now transmitted directly between ServerB and ServerC. Second, you can enable direct Agent to Agent communications. In the scenario presented above, SureSync on ServerA will still control the synchronization but the data being synchronized will be transmitted directly between the two remote SPIAgent machines. In order to accomplish this, a few steps must be performed:
  • The default SPIAgent port range of 9002-9033 must be open in all firewalls between all machines. ServerA must be able to communicate with ServerB and ServerC on that port range. ServerB must be able to communicate with ServerA and ServerC on that port range. ServerC must be able to communicate with ServerA and ServerB on that port range. If any machine cannot communicate on 9002-9033 to the others, communication problems will surface.
  • Once the ports have been verified open, you must stop your synchronization jobs if running. Once the jobs are stopped, go to the General tab of the Relation(s) in question. Select each root path one at a time and click "Edit". Go to the "SPIAgent" tab and check the option "Agent for this path can send to all other paths in this Relation". Once all the paths have been modified, the jobs can be restarted and communication will occur between the remote SPIAgent machines directly.