So why do you need additional copies of your data? In a disastrous incident it is expected that the data center or technology is gone and no longer functioning. In order to continue your processing, you must restore the data which you have stored in the data center on some media via your data replication process. Without this data you would have no historical data to process. Having a copy or replica of the data gives you the chance to at least pick up close to when you were impacted by the interruption, once the data is restored on comparable equipment.
What type of remote data replication you choose is dependent on the operation affected. A transaction-based operation would require a fast turnaround and short intervals between backup, but a batched environment could take longer periods between data backups. These timeframes are defined as your recovery time objective (RTO), or time to set up the technical environment for operation, and your recovery point objective (RPO), amount of tolerable data loss. Ideally the RTO and RPO are very close.
This was first published in May 2010