# HA_Cascade

> This sample demonstrates how to use cascade replication in eXtremeDB High Availability. The master application creates and populates the database, then enters a loop creating and deleting objects as it waits for connection requests from replicas. The `hacascade-rplmst` application connects to the "master" and synchronizes with the master database. At the same time `hacascade-rplmst` works as a master, i.e. waits for connections from other replicas on port 20000. (Note that `WRITE` transactions are not allowed, because it is a replica for "master".)

### How to Run

> See instructions here on how to build this and other samples on your development platform. Once built, the sample can be run from the `\target\bin` directory.

> In a console window run:

>         hacascade_master

> Then run one or several "replica" applications:

>         hacascade_rplmst

> Then run one or more "replica" applications, that connect to rplmst and synchronize with its database:

>         hacascade_replica

> Note that the database updates from the `hacascade_master` go to `hacascade_rplmst` and then to the second-level `hacascade_replica` applications.

> But it is more instructive to run one instance in your development environment debugger, stepping through the code.

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