Understanding SaaS migration benefits and best practices

Why should you migrate to SaaS?

A SaaS migration provides benefits besides breaking free of a legacy application for which the vendor offers few replacement options. Many businesses do it because it enables them to move IT costs from the capital side of the financial ledger to the operations side, which can be easier to justify to executives and enables the organization to spread out the expense of upgrades and support.

In addition, turning over the keys to a SaaS provider takes most of the worries off IT's plate. If there's an issue, it's probably an issue for everyone, and the SaaS vendor can put more people to work on a fix than any single customer could.

The oft-repeated downside of multi-tenant SaaS is that customers must give up control. The truth is they never had much control. A bad software patch or local hardware failure often meant waiting on hold for technical support or for parts to be shipped to the data center. Moving to multi-tenant SaaS also helps avoid the stress on IT staff from being on call 24/7; with multi-tenancy, it becomes the SaaS provider's problem.

Another major benefit of moving to multi-tenant SaaS is it transfers most of the responsibility for audits, compliance and security to the provider. All three are critical and must happen, but they don't contribute to the company's profits. The SaaS vendor takes them on because it wants the subscription revenue, and customers can hold it accountable for these and other items promised in a service-level agreement.

SaaS migration models

Here's an explanation of four common SaaS migration approaches and the pluses and minuses of each.

• Siloed. In a siloed migration, a single application is moved to single-tenant SaaS, which avoids the sharing of data and infrastructure and provides more control over data and its location. Think of it as a relatively simple "forklift" of an application.
  
  Siloed migration is usually the most expensive option because it gives the customer the most control over the computing environment. But it also doesn't take full advantage of the cloud's benefits, especially economies of scale. Over time, the cost of this single-tenant migration method will likely exceed that of a move to multi-tenant SaaS.
• Layered. In a layered migration, applications move to the cloud bit by bit, effectively enabling the organization to stick its toes in the water. The emphasis is on stability and system integrity.
  
  Layered migration can be ideal for a company that has a lot of homegrown software and wants to move into the cloud at its own pace. The process can be labor-intensive but lets risks and costs grow at a comfortable pace. Layered migration stretches the cost out more over time but can save money over siloed migration in the long haul, thanks to better resource use.
• Data. In a data migration, just the data from the on-premises application is moved to a new SaaS application. This is the approach taken by software vendors that stop offering on-premises products.
  
  Such a move might seem risky, but vendors provide lots of tools to help make it a success. The biggest downside is losing most or all of the customizations made to the on-premises application. Multi-tenant SaaS can't allow extensive customization because large numbers of customers have to share the same environment.
• Parallel. In a parallel migration, the organization gets a second computing environment up and running so the application and associated infrastructure can be cut over quickly and easily once testing and validation are done.
  
  Parallel migration is the safest option but also the most expensive. It tends to be on many organizations' wish lists. The problem is many of them keep the old system online longer than necessary, paying for up to a year for power and maintenance to hold onto what is essentially a security blanket.

Which of the four options a company chooses will be based on a variety of reasons, especially cost, security, ease of implementation and availability. But one of the biggest deciding factors, not surprisingly, is the original application itself. If it was developed in-house, the organization would probably look at either a siloed or layered migration, with the latter being a bit more popular due to the cost savings. If the application in question is a commercial application, the transition will probably come from a data migration or a parallel migration. Lower cost and easy availability of data conversion and importing tools from vendors make data migration the somewhat more popular choice.

Challenges of a SaaS migration

The many benefits of SaaS migration don't mean the process will be free from issues. For example, a data migration or parallel migration from an on-premises product to a cloud product seems like a slam dunk, but previous modifications and custom settings are likely to get the axe because the SaaS application must be generic enough to meet the needs of different customers. While inability to customize is not likely to derail a migration, it often requires changing some of the organization's standard operating procedures and business processes.

Siloed and layered migrations tend to be more challenging. Homegrown software is far less likely than commercial software to have undergone previous efforts toward migration. Documentation will be key -- and not the usual documentation. IT staff will need to document how the application works, its network paths and even the ports it uses. The spider web of an application's stack can seem overwhelming when companies start digging into the many pieces that make it work. It all needs to be on paper before a single item is moved to the cloud. Without documentation, the company is setting itself up for a mad scramble to disable firewalls because something in the new setup doesn't work and then trying to reapply security -- which tends to leave holes open.

SaaS migration best practices

When considering a SaaS application, the most important thing is to gain a thorough understanding of the application you're looking to replace and its importance to the organization. IT teams and the business departments that use it the most must truly understand what it does, how it works, what it needs to work better and how it has been modified from its base configuration.

Only when you understand and document those things can you start to envision the impact of moving to the SaaS equivalent. Focus especially on three main impact areas: operation, performance and cost. Overlooking one part affects all the others. The biggest one, however, is cost. It's the one that gets noticed every time.

Brian Kirsch, an IT architect and Milwaukee Area Technical College instructor, has been in IT for 30 years and holds multiple certifications.