Backup and disaster recovery have historically been considered separate disciplines, managed with separate tools. However, in recent years, many backup products have added some DR capabilities. But, before we explore how backup and DR are coming together, lets first consider their differences.
Backup vs. DR
The primary function of backup is to create a copy of data, so you can restore back to a point in time before it was lost or corrupted.
To accomplish this, data protection software typically uses a process called incremental backup. First, a complete copy of the data is made (a full backup). After the initial full backup, the software only copies the changes that have occurred since the previous backup (incremental backups). Additionally, the backup software keeps a record of changes over time. To restore, a complete copy of data is “re-built” from the full backup and the incrementals that follow. Then, it is copied back to the production server—assuming it is still operational. So, restores incur some downtime especially for large data sets.
Disaster recovery, on the other hand, is all about reducing or eliminating IT downtime. There are a variety of ways this can be accomplished. Some DR products maintain a synchronized copy of a production server’s data, applications and operating system on a secondary server locally or offsite. In the event of a primary server outage, operations can failover to the secondary server in a matter of seconds. However, changes on the production server are synchronized on the secondary server in real time. So, if data is deleted or corrupted on the primary server, those changes will be mirrored on the secondary server. That’s why many businesses deploy both backup and DR tools.
Backup + DR
As noted above, some of today’s backup software products offer native disaster recovery capabilities. The most common of these capabilities is failover of virtual machines. Here’s how it works: The backup software takes a snapshot of a VM—a complete copy of a virtual server’s data, applications, and operating system. Then, the snapshot is copied to a secondary server. Additional snapshots capture changes to the VM over time and the software keeps a record of those changes, much like the incremental backup process outlined above. Here’s the cool part. If you suffer a primary server outage, you can spin up the backup VM on the secondary server and resume normal business operations. This delivers failover-like recovery alongside the time-based restore and data retention capabilities that backup has always provided. This is appealing to many organizations, because it reduces the number of solutions IT needs to monitor and manage.
However, there is one important caveat you should be aware of. Unlike dedicated failover solutions, restores are not a push-button process. Recovery requires some manual intervention from IT. The same applies when it’s time to failback to the primary server. That being said, restores are still very fast when compared with traditional backup—with downtime measured in minutes rather than hours or even days.
Choose the right tool for the job
Developing a backup and disaster recovery strategy starts with your business needs. How much downtime can your business tolerate? Or a better question might be, how much potential revenue do you stand to lose if your business is offline for an hour? Or, a day? Once you understand those numbers, deploy a solution that can get your business up and running within an acceptable timeframe. It’s like that expression: when all you have is a hammer, everything looks like a nail. Today, there are tools available at a variety of price points that can dramatically reduce IT downtime. When it comes to backup and DR, you’ve got options. Use them.
