Software Applications Programming Errors and solutions.

Log shipping, mirroring & replication are various types of HA (high availability) features. Each of them have their own set of pros and cons and various sets of features. Hence there is no compulsion and requirement to implement all of them. Rather the decision to choose them is driven by business requirement and at times the resources available for use. Db mirroring and log shipping are database level HA the replication is object level HA. If you have SSRS, then go for replication, never keep OLTP database to fetch SSRS reports. Replication is never a DR lets take an example that for your reporting environment you habe used transactional replication. On the reporting database server for best performance you build plenty of indexes which are not required on the OLTP environment therefore I believe clustering mirroring and log shipping are the best option always have a powerful backup strategy that will always help you.