It's common to talk about cloud migration as if it's an all-or-nothing affair. You might be left with the impression that businesses either go all-in on the cloud or stay fully on-prem or in a colocation center.
The reality, though, is that for some organizations, it makes more sense to choose a middle ground. Some workloads migrate to the cloud while others remain on-prem.
Which approach makes most sense for your organization? Should you go all-in on the cloud, or choose a more mixed strategy? Keep reading for guidance as we compare the pros and cons of partial versus full cloud migration.
The advantages of migrating completely to the cloud
There are a number of reasons why you might want to move your workloads completely into the public cloud.
Arguably the greatest is simplicity. Going all-in on the cloud means you only have to manage one environment – your cloud. You don't have to worry about juggling two different sets of monitoring and management tools (one for the cloud and the other for on-prem workloads), or about interconnecting on-prem workloads with cloud workloads. In addition, responsibilities like managing physical hardware and handling on-prem backup disappear when everything migrates to the cloud.
Migrating entirely to the cloud also simplifies matters from a financial perspective. You can predict all of your infrastructure costs based on the billing schedules of your cloud provider, rather than having to account separately for cloud spending and on-prem infrastructure spending.
A third advantage of migrating completely to the cloud is that it maximizes the scalability of your infrastructure. You don't have to worry that some workloads can't scale because they are running on local servers whose capacity is finite.
Reasons to keep some resources on-prem
On the other hand, you can make good arguments for keeping some workloads in private data centers even as you move others to the cloud.
Probably the most obvious reason not to go all-in on the cloud is that some workloads may need to stay on-premises. They may need special hardware that isn't available in the cloud, for example, or compliance or privacy mandates may require them to stay on-prem.
Beyond this, staying partly on-prem offers the advantage of allowing you to reap full returns on investments you've already made in your own hardware. If you move entirely to the cloud, you may end up having to sell off servers at a discount or (worse) letting them sit idle. Likewise, you don't have to worry about finding a good way to repurpose the space you used to use to house infrastructure.
There's an argument to be made, too, that keeping some workloads on-prem is beneficial from a reliability standpoint because it allows you to diversify your risk. If you move everything into the cloud, and your cloud platform fails, everything breaks. If you have some workloads in the cloud and others on-prem, you don't have a single point of failure. (Of course, you could achieve similar diversification by adopting a multicloud architecture, but that's not typically where organizations start if they're just getting underway with cloud migration.)
How to decide between partial vs. full cloud migration
So, when does it make sense to go all-in on the cloud, and when should you choose a more measured cloud migration strategy? The answer depends on a few key factors:
- Workload requirements: If there are technical or compliance-related reasons to keep some workloads on-prem, you'll need to keep them on-prem.
- Manageability: Businesses with less advanced IT functions might benefit from going all-in on the cloud, simply because it's easier to manage a single environment.
- Existing investments: Consider your existing infrastructure and data center investments and determine how much you'll lose if you were to migrate completely to the cloud.
- Scale requirements: Although it's impossible to know for sure how your hosting requirements might change in the future, some workloads are likely to need to scale more than others. If you do expect a lot of scaling for most of your workloads, going all-in on the cloud makes more sense.
If you're struggling to decide, keep in mind that you can always start with a partial cloud migration and then move more workloads to the cloud later. "Repatriating" cloud workloads back on-prem is also an option in the event that you decide you've over-committed to the cloud, but repatriation is a lot of effort – so it's less risky to start with a limited cloud migration and scale up from there, rather than going all-in on the cloud only to back some workloads out after the fact.