In this DB server I have other databases than the default "edb" database. Specifying the above line as pg1-database=edb // I am not sure this line is necessary or not ?
The pgbackrest process needs to connect to the database, which means it needs a user and database. You need this variable if you do not have the default database, "postgres". If you have a database named postgres, you can leave this out. Otherwise, yes, it is necessary.
pg1-database=edb // specifying like this, will it block other databases on this server to get backed up ? IF yes how can I overcome this ?
pgBackRest works on a cluster level, so *all* the databases are backed up. Indeed, it is not possible to only backup some of the databases. It's the whole cluster.
( I am just learning and exploring PgbackRest) found online some reference configurations so using like this )
Probably best to stick to the official docs; this section in particular is worth a read:
