Backup strategies

A backup and recovery strategy has the main purpose of protecting a database against data loss, and this document will contain all steps required to reconstruct the database after a disaster strikes. As the person responsible for the data of your company, it is very important to have a correct backup strategy in place to allow you to recover from any possible disaster.

Before you create a strategy, you will need to understand clearly all the Service Level Agreements (SLAs) in place with in your organization regarding this topic. To that end, you will need to ask some simple questions to the owners of the data:

• How much data can the company lose in case of a disaster? (RPO)

• How much time could the business wait to have the data restored and available again? (RTO)

• How much will it cost the company for the loss of one hour of data?

• What retention periods are required by law for the company data?

After receiving the answers to all these questions, you will be able to implement a proper backup and recovery strategy according to your real company needs and SLAs in place.

For example, if your company can only afford to lose three hours of data (RPO) but it can have the database down for up to 24 hours for a recovery process (RTO), all you will need to do to fulfill your SLA is to have a full backup of your database made daily. You will also need to make backups of all your archive logs every three hours to a tape or another network location to allow you to have all your data protected.

As part of creating a strategy, it is important to properly understand the concepts known as Recovery Point Objective (RPO) and Recovery Time Objective (RTO). As you can see in the following figure, the RPO reflects how much data might be lost without incurring a significant risk or loss to the business, and the RTO is basically the maximum amount of time allowed to reestablish the service after an incident without affecting the company seriously.