Hello Shahid,
PostgresClusters require at least one pgBackRest repository and that a single backup be taken in the first pgBackRest repository defined in the cluster spec when the primary instance of the cluster comes online for the first time. As of right now, there is no way to opt out of these requirements. However, we do have stories in our dev backlog to consider making the initial backup, and the `backups` section as a whole, optional.
Regards,
Drew