Disaster recovery as a service is a great way to use the cloud to reduce the cost of delivering services to your business.
On premises, disaster recovery means creating a complete replica of your production data center at another location, and then replicating data between those two locations. Conversely, having a disaster recovery as a service (DRaaS) provider supply the remote data center and only require payment for what you use may seem like a very attractive option.
DRaaS is popular with businesses that want to consolidate to a single on-premises data center. An informed decision on using DRaaS needs to take into account all of the possible costs and limitations of the DRaaS provider you select. Some costs are immediately evident, while others are a little more subtle, and may depend on how you use the DRaaS product.
The real price of DRaaS
The DRaaS sticker price is usually driven by the service provider's storage requirements, since they need to store copies of your data. This is often what makes DRaaS appealing, as providers use low-cost, scale-out object storage with great economies of scale.
The other highly visible cost is the network link to the DRaaS provider. You need enough network speed to transfer your backups sooner than your recovery point objective to ensure any disaster recovery efforts use up-to-date data. No matter how you use DRaaS, you'll likely get billed for these two costs every month.
Storage does end up being more costly if you also use the DRaaS repository for data retention and compliance purposes. Typically, a disaster recovery effort only needs to retain the last couple of restore points, while other purposes may require far more, and far older, restore points. Be mindful of the price per gigabyte of data stored.
A less obvious cost is in testing your DR plan. Some DRaaS providers include a single DR test per year with their service, while others may require you to pay for every test. If you're planning on using the free test offered by the DRaaS provider, watch out for time limits on the compute resources included in the test. Extra costs could pile up if you need a week to complete all of your verification tests and sign off on the plan. If your compliance regime mandates DR tests every quarter, costs can add up even further.
Failover, failback can become costly
Enacting DR plans to recover from the catastrophic loss of a data center is extremely rare. A DR failover is more often a protective action to avoid a disaster.
With DRaaS, there are costs associated with compute in the cloud when you fail over. Having to pay this extra fee may lead some organizations to decide not to fail over when dealing with lower risk events. For example, is it worth spending $10,000 to fail over to the cloud when a storm may not flood the building?
Then there is the real nightmare: failback. Once you have failed over all of your production systems to a DRaaS provider, how do you get them back? That $10,000 price tag to fail over during a disaster is nothing compared to the $10,000 per day fee you will be charged while your production is in the cloud. You therefore need to replicate data back from the provider.
Depending on the provider, you may get a bill for data egress from the cloud. A dedicated DRaaS provider is less likely to bill you, but an infrastructure as a service provider that dabbles in DRaaS might.
Then there is the actual failback once the data is replicated. Have you tested that? Maybe you chose some disposable virtual machines and tried to round trip them into the DRaaS and back out. There can be a significant labor component to some failback processes, resulting in additional costs.
You also need to factor in lost opportunities. A DR data center is seldom a dark and ignored place. Far more often, DR servers are used for non-production purposes. It can be as simple as being a training ground for the IT team, or as big as the entire development environment being housed on the DR servers. With a DRaaS provider, you relinquish the ability to get value from those servers when you give up the cost of owning them.
Like so many cloud services, DRaaS has the promise of a lot of business value. Smart businesses will look beyond the sticker price and evaluate how they will use a DRaaS provider, and what they give up in return.
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