When it comes to disaster recovery planning, it is important to understand the underlying concepts with utmost clarity. RTO and RPO are the essential KPI's that should dictate your disaster recovery guidelines.
You need to have a clear idea on what these are and how to distinguish between them.
What is RPO?
In order to create an appropriate disaster recovery plan, it is important to understand the concept of Recovery Point Objective (RPO).
RPO is the age of the lost data that must be recovered so that normal operation could be resumed after a system failure. It is the parameter based on which the disaster recovery plan determines which files are to be backed up and at what frequency.
RPO Real-Life Example:
Imagine that you host an e-commerce website that has 1 transaction every 3 hours. If you experienced data loss and needed a backup restoration, you want to make sure that you don't lose even a single transaction.
So you'd want at the mimumum to be able to restore back from 3 hours ago. Dealing with the loss of 1 transaction is manageable (maybe), but 4 transactions crosses the chasm into the realm of full scale emergency.
Customer Tip: Database Replication is more effective than backups for busy databases.
What is RTO?
RTO stands for Recovery Time Objective. It is basically a service level agreement that protects the business continuity of your hosted website or application.
RTO can be defined as the target time-frame within which a system must be restored after a disaster without affecting the business continuity. It is a measure to keep the consequences of any disaster limited to an acceptable extent.
RTO Real-Life Example:
For example, lets say that host a mobile game application. How much time (minutes) can you afford components of your stack to be down? After how many hours of downtime will the users of your mobile game application be so angry, that they'll simply erase your app, and download one of your competitors?
RTO helps define your expectations of how much exposure time you can afford to endure. Every minute you're offline means higher risk of bad publicity, angry customers, and lost revenue.
Every online business needs a documented disaster recovery plan. And formulating this disaster recovery plan begins by honestly defining your recovery point and recovery time objectives.
We cannot stress enough how important it is to implement backups that are in line with your business requirements. An incremental or full backup schedule is probably sufficient for most customers with a low to mid-range RPO and RTO objective.
But for organizations that deal with large volume of sensitive data, they should consider the prospect of more advanced disaster recovery services like offsite data vaulting and real-time database replication, if they intend on realistically achieving aggressive RTO and RPO objectives.