5 Replies Latest reply on Jul 30, 2009 1:20 AM by Yong Hao Gao

    JBM replication needed?

    Frank Henry Novice

      I am working on replicating the database for a simple failover system and was wondering if I need to replicate the data for JBoss Messaging?

      If so, is it somehow possible to tell JBM to use a specific schema of an already existing database?

      I'm using slony1 and it would be a lot easier to only have to handle one database and it's schemas and tables.

      System:
      JBoss 4.2.3 with JBM 1.4.4
      PostgreSQL 8.3 database

        • 1. Re: JBM replication needed?
          Yong Hao Gao Master

          JBM 1.4 has its own database schema. Considering using bridge to import your existing data to JBM.

          • 2. Re: JBM replication needed?
            Frank Henry Novice

            What I meant with schema is the database schema you can normally set via the orm.xml.
            Thus I could hang the JBM stuff not into it's own database but could add it as an other db schema to an existing database.

            Are we talking about the same thing?

            I have no issues with importing the data.
            Slony just requires one complete replication system *per database*.
            So the less databases I have, the better. (I am down to just one + JBM atm)

            • 3. Re: JBM replication needed?
              Yong Hao Gao Master

              I'm not sure I understand you completely. I don't know Slony. But as long as JBM is concerned, one DB instance is enough for each JBM server, or each JBM cluster (where all nodes in one cluster share one DB instance).

              If your replication system have access to the same DB, make sure their table names don't clash with JBM's.

              • 4. Re: JBM replication needed?
                Frank Henry Novice

                Slony only does master-slave replication.

                Setup:
                DBs A (master) and B (slave)
                AppServer cluster with both A and B in their datasource list.

                So in the normal case all cluster nodes connects to A (alas a shared database).
                Slony externally replicates the database from A to B.

                Now if A fails, the AppServers switch to B.
                (the replication terminates in the background).

                Question is, do I even need to replicate the JBM database to the slave?
                As I have no idea how JBM persists it's data, I am unsure of this.

                F.i. do the pre-failover messages still exist after failover if they were not replicated?
                i.e. these messages are lost and would cause the subscribers to miss them.

                If I do, then I wonder if it is possible to tell JBM to persist it's tables in a specific schema of the database in order to simplify the replication.

                • 5. Re: JBM replication needed?
                  Yong Hao Gao Master

                  Thanks for clarification. In that case you need to replicate all the JBM tables from A to B. JBM doesn't have the facility to help.