Should we delete config/currentView before reconfiguration?

[chenweiyj]

I start replicas in the same build/ folder and use the identical config/currentView file. At first, I start the system with 4 replicas, and the first starting replica creates the currentView file. Then, I reconfigures to add more replicas to the system one by one without deleting the currentView file. Afterwards, the new replicas print the configuration information at beginning, showing always F=1. So I wonder whether those replicas including old ones can adjust F and quorum automatically after new replicas are connected, or I should delete config/currentView before starting new added replicas.

[rvassantlal]

The quorum will adjust automatically based on the current values of f and n. However, updating f must be done explicitly using the special reconfiguration client (just like when adding new replicas, which updates n).
Please, see the example presented in src/main/java/bftsmart/reconfiguration/ReconfigurationTest.java.

If you need help, feel free to ask.

[chenweiyj]

Ok, I see. Currently I use ./smartrun.sh bftsmart.reconfiguration.util.DefaultVMServices 4 127.0.0.1 11040 11041 to add a new replica. Do you mean there is no command provided to set f, and I should manually modify DefaultVMServices to create a method to support setting new f?

[rvassantlal]

src/main/java/bftsmart/reconfiguration/Reconfiguration.java provides a simple API needed for reconfiguration. DefaultVMServices and ReconfigurationTest use this API to reconfigure the system.
For now, you will have to either modify DefaultVMServices or ReconfigurationTest, or implement a new class to use Reconfiguration. In future, the goal is to have a better solution that does not require TTP.
You can use Reconfiguration in the following way:

1. Parse reconfiguration parameters (either from the command line or from a file);
2. Instantiate a Reconfiguration object rec;
3. Invoke addServer/removeServer/setF on rec;
4. Invoke connect on rec;
5. Invoke execute on rec;
6. Invoke close on rec;

NOTE: When instantiating the Reconfiguration object, use the id defined in the parameter system.ttp.id of system.config file.

If you prefer extending DefaultVMServices, you can first implement a method in VMServices, similar to addServer/removeServer, that invokes setF from ViewManager. Then modify DefaultVMServices to receive new f from the command line and invoke the implemented method.

[chenweiyj]

Ok, thx~ I will try this method.