5 steps for mainframe migration

Mainframes endure as a know-how stalwart some 60 years after their invention, shouldering essential, transaction-intensive workloads.

Almost three-quarters of the U.S. IT choice-makers Forrester Analysis polled for a 2020 research stated mainframes have lengthy-term viability as a strategic platform — fairly a vote of confidence. That stated, some clients is perhaps trying to half with huge iron. Mainframes can show pricey to take care of and businesses wrestle to seek out individuals& who understand legacy languages and databases. As well as, the attraction of cloud computing as a versatile, trendy IT setting means many mainframe adherents will move at the least some of their purposes and knowledge to as-a-service options. Getting there won’t be straightforward.

Mainframe migration is a sophisticated chore that calls for cautious planning and an assessment of choices. The alternatives embrace shifting the whole mainframe surroundings to a hosting providers provider or refactoring a mainframe software for deployment in a public cloud or another platform.

Whatever the technique, nailing that transition is essential for IT outlets still counting on the mainframe’s compute power.

“The mainframe is the backbone of their organizations — it is sometimes driving the transactions that make these corporations run,” stated Ken Marr, CTO at FNTS, a managed IT providers provider based mostly in Omaha, Neb. “It is a massive deal to move these purposes and rewrite them.”

Mainframe migration in 5 steps

Companies planning a mainframe migration should contemplate myriad elements, including their time-frame for the venture, price range, the expertise required to rewrite mainframe purposes and the criticality of the purposes to the business.

Chart of mainframe options for enterprises
Businesses face several determination factors as they think about the destiny of mainframes.

Listed here are the important thing steps in the mainframe migration journey.

Step 1: Contemplate mainframe rehosting choices

A corporation determined to desert mainframes however with limited time to do so may investigate mainframe rehosting. The strategy is available in several flavors — mainframe as a service, outsourcing and emulation, to name a couple of — however they all boil right down to shifting the mainframe software from a buyer’s on-premises knowledge middle to a service supplier’s cloud.

Rehosting, as a raise-and-shift migration, does not involve an in depth software program rewrite. That makes it quicker and less expensive than different migration strategies.

Hosting appeals to “individuals trying to find a cloud surroundings for his or her mainframe workloads without rewriting them,” stated Juan Orlandini, CTO for the North America branch of Perception Enterprises, an IT providers supplier based mostly in Chandler, Ariz. “What you’re doing is eliminating the on-premises burden that you simply sometimes have with the mainframe and shifting that to a unique location.”

Rehosting also helps clients meet deadlines. When a corporation decides it’s time to get off the mainframe, it may need a yr to 18 months to take action before its on-premises hardware and software program approach up for contract renewal, Marr noted.

These time frames, nevertheless, are usually inadequate for sorting a buyer’s mainframe estate and reworking purposes. But mainframe internet hosting buys corporations some time and offers a steppingstone towards modernization.

“It provides them the runway they want for software rationalization and transformation,” Marr stated.

FNTS, which provides its own cloud for internet hosting IBM Z-collection mainframes, is among the many service suppliers providing mainframe outsourcing. Others embrace Ensono, an MSP and know-how advisory agency in Downers Grove, Sick., and IBM, the mainframe maker itself. IBM hosts mainframes via its IBM Z compute Digital Server Occasion that runs in an IBM digital personal cloud.

Step 2. Refactoring? Start with an software evaluation

Clients may choose to migrate mainframe workloads. This technique includes refactoring code, which means rewriting all or part of an software to make the most effective use of cloud providers. Refactoring is more time-consuming and expensive than hosting but has larger transformative potential.

“The refactoring mannequin provides the appliance a brand new lease of life,” stated Oliver Presland, vice chairman of the global consulting providers portfolio at Ensono. A refactored software can more simply integrate into cloud-native providers and ultimately evolve into a microservices architecture, he added.

This feature, nevertheless, ought to begin with an assessment of the mainframe software or set of purposes to be migrated.

“There’s a technical factor to that, which is knowing the codebase, the dependencies and the interactions with external interfaces and techniques,” Presland stated. “Should you do not spend time on the evaluation part, understanding how you’ll rework that software, you then’re operating the danger that the undertaking will hit some challenges along the best way.”

Orlandini additionally cited the importance of beginning with a elementary grasp of the mainframe system to be migrated.

“It boils down to really understanding what your software is doing for the business and what enterprise logic it is encoding and the right way to more effectively recode that,” he stated.

Marr stated this software rationalization step helps organizations decide the art of the attainable. With that information, a enterprise can devise its strategy for shifting workloads off the mainframe or, alternatively, determine either to retain its software on the mainframe or retire it.

Step 3. Be careful for the robust bits

Clients opting for refactoring should contemplate a complexity evaluation to determine potential migration hurdles.

Automated tools assist with the conversion of widespread mainframe technologies — comparable to COBOL, PL/1 and VSAM knowledge information — to trendy languages and knowledge formats. But such choices won’t exist for the extra obscure code residing on the mainframe.

“Whilst you may move the majority of your purposes and knowledge with quite a lot of options, discovering a option to cope with a number of the more exotic [technologies] can develop into quite challenging,” Presland stated.

An software may include, for instance, very particular code for a specific enterprise objective or a specialised third-social gathering plugin, he famous. And the backward compatibility of IBM mainframe environments signifies that previous code and archaic techniques can still run on newer hardware.

Presland cited the instance of Mannequin 204, a Nineteen Seventies database management system. He estimated Ensono has carried out three sizeable Model 204 transformations. “It’s extremely troublesome to seek out the talents and employees for those,” he added.

Staffing is indeed an issue, since many technicians adept within the arcana of mainframe methods have retired.

“These may be 40-, 50-yr-previous purposes,” Marr stated. “Having someone who knows the code nicely might or will not be the case.”

Typically, purposes concerned in decrease-volume transaction processing are probably the most problematic. “The excessive-quantity pieces usually are not a problem as a result of [they] are typically written in widespread languages,” Presland stated. “The low-volume-however-crucial pieces of the appliance portfolio are really key. They have been written a long time in the past and also you want to be able to rework these.”

Figuring out the toughest code conversion problems upfront helps with migration undertaking planning.

Step four. Plan the challenge

A radical software evaluation and complexity evaluation feeds into the migration challenge plan.

The refactoring model provides the appliance a brand new lease of life.
Oliver PreslandVice chairman of worldwide consulting providers portfolio, Ensono

“That lays the inspiration to say, ‘I perceive the enterprise case and I perceive the know-how path,'” Presland stated.

The result’s predictability on the subject of the undertaking timeline, worth, the tactic for dealing with complicated elements and a necessities/useful resource plan, he added.

Ensono’s undertaking planning gives clients a couple of ways ahead: an instantaneous transition to migrating mainframe workloads, or a proof of idea with full migration to comply with. The latter includes converting the primary part of the appliance to be migrated. Changing a piece provides the client something to check and run — which offers a confidence increase, Presland stated.

Different migration approaches may start with a couple of code modules to point out the method generates good high quality code. But this demonstration does not present a working system that the client can check, he famous.

Step 5. Covert the code

Refactoring requires changing code written in previous languages to trendy ones, reminiscent of Java, C# or COBOL 6.0. Knowledge maintained in flat information or nonrelational formats is transformed to a relational database format, typically a PaaS database, Presland stated.

IT service suppliers specializing in mainframe conversion use device units to automate the conversion activity.

Marr estimated mainframe code instruments obtain a conversion accuracy proportion within the low 90s. Converting the first 92% or ninety three% of the code can go moderately shortly, but changing the remaining code to make the appliance work takes time, he added.

“It is still an enormous challenge, however it’s far quicker than totally rewriting an software in C#, C++ or Java,” he stated.

Businesses can extract particular person transactions from an software to scale back the conversion burden. A financial institution, for example, may focus solely on the verify-stability perform of a customer-dealing with mainframe software and migrate that piece, relatively than the complete system.

“Most corporations take a look at it on a transaction-by-transaction foundation,” Marr stated.

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