BUG #3758: Postmaster Service

The following bug has been logged online:

Bug reference: 3758
Logged by: Sudarshan V Tantry
Email address: sudarshantantry(at)gmail(dot)com
PostgreSQL version: 7.8.2
Operating system: Redhat Linux 3
Description: Postmaster Service
Details:

We are supporting a messaging system in which there are two application
servers with cluster services.Cluster service does the job of shifting the
Application and Database services from one server to another if one of the
Application servers goes down.

Now,the problem is when we were testing the automatic shift over of
services,by manually stopping cluster service on one server using the
command "service clumanager stop" the Application and Database services get
shifted to another server,but Application services would be down due to the
fact that it cannot connect to the Database services since the postmaster
service is down.We check the status of Postmaster service with the command
"pg_ctl status".Even if we start the Postmaster service manually it goes
down whenever we stop the cluster service to shift the services back to the
first server.
Also postmaster services do not start even when the server is restarted.
We checked the postgresql.log in which we could find this:
Unable to connect to database
Cannotfind /var/lib/pgsql/DBDATA/data/postmaster.pid

DBDATA is the database service that is mounted on the application
server.That is getting mounted but postmaster would be found stopped.

Please let me a solution for this problem and also tell me why this problem
occurs.