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Is mainframe application migration a good idea?

I currently have banking applications on a mainframe platform. Is it possible to move them onto servers? What are the adjustments and risks involved?

There are precedents for moving mainframe applications to other servers, but there are also several adjustments and risks involved.

Application reengineering started in the 1990s. The mainframe was supposedly dying, so applications were rebuilt to run on other types of servers.

The data center industry formulated several mainframe application migration methods. You can forklift the application in an emulation mode onto distributed servers, rebuild applications by rewriting them for the new system or find a replacement application that already runs on distributed servers.

Physically getting an application to run on new servers is only one consideration.

Workflows might change via business process reengineering to allow other applications and workflows to use the data on distributed servers.

Also consider security. The mainframe is an Evaluation Assurance Level 5+ environment, the strongest security rating in the computing industry. Reevaluate your security precautions if applications migrate to other platforms, especially when you're working with applications for the banking and financial industries.

Data proximity is also a potential issue. Generally, the closer data is to a processor, the faster the application performs. If you move the app to distributed servers, processing speed will decrease. If you choose to snapshot data from a mainframe to a distributed server and then massage that data, it could create a data management issue.

If you undergo a mainframe application migration to a distributed computing environment, performance might suffer. Most IT professionals don't understand the mainframe's huge I/O subsystem that enables it to deal with large volumes of information and transactions. Mainframe processors can focus on compute activities as opposed to managing I/O. Determine whether that distributed environment has the resources to match the mainframe in terms of I/O processing. It might mean that the right distributed environment hardware and software costs significantly more than the mainframe.

About the author:
Joe Clabby is the president of Clabby Analytics and has more than 32 years of experience in the IT industry, with positions in marketing, research and analysis. Clabby is an expert in application reengineering services, systems and storage design, data center infrastructure, and integrated service management. He has produced in-depth technical reports on various technologies, such as virtualization, provisioning, cloud computing and application design.

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How did you migrate business applications off of the mainframe? Was the result successful?
I agree wholeheartedly with the comments made in this answer - particularly the final line "It might mean that the right distributed environment hardware and software costs significantly more than the mainframe." Personally it would change the word "might" to "will". As the author notes, the power of the mainframe's I/O systems are such that things such as load balancing and database synchronization are just not needed. In a multi-server environment they are a fact of life.

The one question that was not posed was "Why move?" - What is the motivation? In my experience the desire to make such a move is often driven by a combination of a lack of understanding of the true costs of migrating coupled with a lack of understanding of what can be done in the way of modernization with the existing applications.

For many IBM mainframe users, if cost savings are a motivating factor, a switch to IBM i on Power hardware is often a viable option if the mainframe apps were developed in COBOL.   
We use IBMi for a large SAAS offering.  Would have it on no other platform due to security, speed (firmware embedded SQL!),reliability and TCO. 
Good points brought up. The question itself gets the typical IT response: "It Depends". A little like ... do I need to get a divorce? Different people have different answers, but it is a serious move to do so, and should be taken only if the current situation is completely untenable (my lovely wife and I just celebrated our 30th). It can be costly, and there is great risk involved. That Cobol that has been running for 30+ years has lots of nuances in it. So it's not IF you will find problems down the road, but when, and how bad. Cloud technology is improving constantly, and providing more and more of what mainframes have provided for decades. Ironically, the costs are looking a little more like mainframes as well if you get all of the "must have" management, monitoring, service, security, and admin software. Long story short, the answer is still, "It depends".