Recovery point objective
From Wikipedia, the free encyclopedia
Recovery Point Objective (RPO) describes the acceptable amount of data loss measured in time.
The Recovery Point Objective (RPO) is the point in time to which you must recover data as defined by your organization. This is generally a definition of what an organization determines is an "acceptable loss" in a disaster situation. If the RPO of a company is 2 hours and the time it takes to get the data back into production is 5 hours, the RPO is still 2 hours. Based on this RPO the data must be restored to within 2 hours of the disaster.
Example: If there is a complete replication at 10:00am and the system dies at 11:59am without a new replication, the loss of the data written between 10:00am and 11:59am will not be recovered from the replica. This amount of time data has been lost has been deemed acceptable because of the 2 hour RPO. This is the case even if it takes an additional 3 hours to get the site back into production. The production will continue from the point in time of 10:00am. All data in between will have to be manually recovered through other means.
[edit] Calculating RPO
Calculating RPO for a specific replication element (disk, storage volume) is relatively straight forward. Most replication mechanisms enable the user to receive the information through API or Command Line. The RPO is usually measured in time (typically seconds) or dirty tracks (tracks that changed in the master copy but did not change in the replica). Measuring RPO for entire data sets (database, file system, application data) is more complex and requires using the lowest common denominator of all the physical elements protecting the logical data set. For example: Calculating the RPO for an Oracle database that resides of 10 storage volumes requires understanding which storage volumes contain the database, requesting the information of RPO for each of those volumes and using the highest number for calculating the RPO. Additional complexity arises when not all physical volumes were replicated at the exact same time. In such case - the replicated data set might be invalid and therefor cannot be relied upon.
Commercial tools for measuring RPO:
- Continuity Software - RecoverGuard™
- Symantec - Disaster Recovery Advisor™
- EMC - Data Protection Advisor™
The RPO in conjunction with the Recovery Time Objective (RTO) is the basis on which data protection strategy is developed.
[edit] References
- Glossary of Business Continuity & Technology Terms
- Why you need disaster recovery management
- Recovery_Consistency_Objective
 |
This business-related article is a stub. You can help Wikipedia by expanding it. |
