– What is the longest tolerable outage? – When must normal operations resume after a disaster?
• Recovery Point Objective (RPO):
– How much data loss is tolerable? – What is the cost and impact of losing this data?
Last copy of data in usable state
Systems recovered and operational
Recovery Time Objective and Recovery Point Objective are important and measurable criteria for evaluating the right backup and DR solutions:
Recovery Time Objective (RTO) describes the time within which business functions or applications must be restored (includes time before disaster declared and time to perform tasks). Recovery Point Objective (RPO) describes the point in time to which data must be restored to successfully resume processing (often thought of as time between last backup and when outage occurred).
Many solutions are available, depending on the recovery objectives. When looking at RPO, one consideration is the cost of some data loss. A corporation may prefer having the ability to quickly perform a database restart instead of an option of no data loss. For other companies, such as financial institutions, data loss is not an option. Any transactions lost since the last backup point must be re-entered into the recovered database, if necessary by hand. Financial institutions keep multiple logs of each transaction so that they can be sure that they can reconcile each account.