Before running GroupPac, be sure that the HTTP server chosen (supplied by the GroupPac package or other) is functioning and that the NS_Ref file is available.

GroupPac is constituted by some modules (or objects) that they can be distributed in many independent machines. These objects are:

• The HTTP server (HTTP), responsible for serving the Name Server reference;
• The NameServer (NS), responsible for registering the references of other objects;
• The ReplicationManager (RM), object groups manager and a tool of control for the administrator;
• The GenericFactory (GF), factories of replica objects that are responsable for the creation and removal of replicas;
• The HostFaultDetector (HFD), detectors of machine faults;
• And the JFTAdmin, a user interface for controling the ReplicationManager.

The JFTAdmin interface and its commands are explained in another page.

Each one of the other modules does not present any direct interaction with the user, and they behave as Unix daemons.

All the objects can be runned in different machines, with only one restriction: the NameServer must have access to the system of files of the HTTP server to be able of modify the content of the NS_Ref file. This file will contain the reference (IOR) of the NameServer, and all the other objects will access the HTTP server to get this reference.

The initialization of the different objects from GroupPac is made with the following line of command in a prompt (be sure that you correctly configured the Java virtual machine and created the properties file):

> main.bat [parameters]

-http

- htdocs < root directory of the server - standard: current directory > 
- htport < number of the port where the server listens - standard: 80> 
- htbacklog < number of simultaneous connections - standard: 5> 
- h - shows a help screen

-ns <file of the NameServer reference>

-h - shows a help screen

-rm

-ft_domain_id <FTDomainId - standard: "DAS/LCMI">
-h - shows a help screen

-gf

-no_monitor - does not show the control graphical interface 
-h - shows a help screen

-fd

-no_monitor - does not show the control graphical interface
-h - shows a help screen

It is not necessary to launch a virtual machine for each object, they can be launched together, for example, to launch the HTTP server and the NameServer just type:

> main.bat -http -htdocs c:\temp -ns c:\temp\NS_Ref

It is important to notice that in the command line of the HTTP server and NameServer it must be chosen where the NS_Ref file will be recorded (command line of the NameServer) and which folder will be available through HTTP (command line of the HTTP Server). In the example the chosen folder is c:\temp.

Attention: It is necessary one GenericFactory for each created replica, which means that if you want to create a group with three replicas, you must have three GenericFactory running.

The HostFaultDetectors are responsible for detecting the machine faults, when a machine stops answering.

The objects ReplicationManager, GenericFactory and HostFaultDetector indicate after the initialization, with a message in the console, when they are ready to receive communications.

Go to the page about JFTAdmin to know how to manage the fault tolerance infrastructure.