Today, nearly all backup and disaster recovery vendors use cloud services in some way. Even so, there are major differences between cloud DR and disaster recovery as a service.
Prior to the mainstream acceptance of public clouds, organizations that wanted to ensure the continuity of business following a disaster would implement a disaster recovery platform. This meant creating an infrastructure that would enable mission-critical workloads to fail over to either a secondary data center or to a colocation facility. Although this approach worked, its high cost meant that disaster recovery was only an option for the largest companies.
Today, disaster recovery capabilities are far more accessible than they once were because the cloud can be used as an alternative to a secondary data center or colocation facility. As the cloud has matured as a disaster recovery platform, however, two main options for disaster recovery have emerged: cloud DR and disaster recovery as a service (DRaaS).
What is cloud DR?
The term cloud DR has historically been somewhat ambiguous. Some publications define cloud DR as the practice of either using the cloud as a backup target or replicating backup snapshots to cloud storage. In reality, these practices are better defined as cloud backup rather than cloud DR.
True cloud DR is based on the idea of being able to fail a workload over to a cloud-based virtual machine in the event of an outage. Although DRaaS providers do essentially the same thing, there is one key difference between the two techniques. Cloud DR is a do-it-yourself approach to disaster recovery. An IaaS cloud such as AWS or Microsoft Azure takes the place of a secondary data center or colocation facility. It's up to the organization to figure out how to replicate workloads to the cloud and how to initiate a failover should the need arise.
How does DRaaS differ?
In contrast, DRaaS providers specialize in cloud-based disaster recovery. These providers offer a ready-made platform that automates workload replication and failover. DRaaS providers also commonly offer tools that can help organizations perform a fail back once the cause of the outage has been repaired.
Ultimately, DRaaS and cloud DR are two different approaches with a common result. Even so, neither approach is clearly superior to the other. Rather, there are pros and cons associated with both methods.
Cloud DR pros and cons
The primary advantage to using cloud DR is that it's extremely flexible. Organizations have complete freedom to design a platform that fully addresses all their requirements, even if it means building a disaster recovery platform that spans multiple clouds.
The disadvantage to cloud DR is that it requires significant expertise. The organization's IT staff will need a strong working knowledge of cloud services, disaster recovery techniques, virtual networking and other disciplines.
DRaaS pros and cons
Conversely, DRaaS tends to be much easier to use but less flexible. DRaaS providers base their entire business on helping their subscribers avoid an outage in times of disaster. As such, these providers will have generally gone to great lengths to create reliable platforms that can be counted on to keep critical workloads running.
There are, however, at least two potential disadvantages to using DRaaS. First, DRaaS is a prebuilt platform, so it isn't as flexible as cloud DR. In fact, some DRaaS providers take a one-size-fits-all approach to protecting their customer's workloads.
A second potential disadvantage is that a DRaaS provider might be ill equipped to handle a large-scale disaster. If an entire region were to be devastated by an unthinkable disaster, then numerous organizations within that region would initiate a DRaaS failover at the same time. The DRaaS provider might not have enough bandwidth or hardware capacity to handle so many simultaneous failovers.