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Mainframe Legacy Decommissioning(1/2)

In the new era of digital transformation, new strategies and technologies are taking over the legacy applications to run the day to day business. As a result of new technologies driving in, when new digital next generation aligned applications are deployed to production, many of the mainframe legacy applications become redundant .The business value of these mainframe legacy applications decreases with every passing year, but organizations often continue to support them for the purposes of data access and compliance. The cost of doing so can consume over 50 percent of an overall IT budget. Decommissioning will enable organizations in eliminating maintenance costs, associated hardware and software costs of these outdated legacy systems.


Application decommissioning is all about isolating the application by migrating the database to archival system, removing the interfaces for upstream and downstream systems and detaching the allocated hardware from its active use, while the business-critical data is still available to the application as is and when required. Typical examples/drivers of decommissioning include:

ยท         Retiring an old application, which has more functional and technical capable alternative system.

  •          Consolidation of one or more in-house applications or COTS products into a single enterprise solution such as ERP, CRM etc.
  •         Elimination of redundant applications within the Enterprise landscape
  •         Mergers and acquisitions of the organizations.


Benefits of Decommissioning:

By decommissioning outdated, redundant, high cost and low value applications organizations can achieve tangible benefits as below :-

  •          Reduction in maintenance costs by removing unwanted hardware, outdated software and human resources.
  •         Financing new business initiative or projects  by utilizing unconstrained resources from decommissioning projects
  •         Expenditure reduction on licenses and infrastructure of non-scaleble technologies.  
  •         Reducing operational risks by simplifying and aligning the enterprise to next Gen Architecture.


All data from a proposed decommissioned legacy system or application may or may not be migrated / archived to the newer replacement system. This depends on the driving factors of application chosen for decommissioning, business criticality and technical adequacy of the system and the impact of the decommissioning on existing enterprise architecture and business processes. I will cover the data migration and archival options in the separate blog.

Application decommissioning best practices suggest archiving all of the data at once while maintaining online access to the data through a preferred reporting tool.

Infosys application decommissioning methodology typically involves following four steps:

1. Portfolio Assessment

2. Detailed Impact Assessment

3. Solution Planning

4. Actual Execution and realization.


Step 1: Portfolio Assessment

In the portfolio assessment phase, the entire enterprise landscape is assessed for each application's life-cycle and identify which applications to maintain, which to invest in, which to replace and which to decommission.

Using sophisticated questionnaire with individual scores mapped to each of the influencing area, the applications are assessed for its Technical maturity, Business criticality along with its Strategic Fitness on organizational road-map and TCO. This is top down interview based approach and by interviewing different Business owners, IT owners and Business Analysts, the application is assessed for its impact on organization, customer service, dependencies on other applications to see if it's a potential candidates for decommissioning.


Step 2: Detailed Impact Assessment

In this phase, we assess the impact of decommissioning on various external and internal interfaces of each application through in-depth analysis.

The impact is assessed by detailed tool based inventory analysis and considering the impact of application on various areas like on access, business, benefits, etc. Infosys has the right set of tools (Combination of In-house and third party tools) viz. Legacy Analyzer, Microfocus Enterprise Analyzer or Averisoruce, in this area which can help and detect the application dependencies, Limitation and risks associated with application and Maintainability index.

The outcome of this step will help us arrive at the final list of applications which will be considered for decommissioning.


Step 3: Solution Planning

The objective of this phase is to identify

  •        Possible solutions for decommissioning the identified applications
  •        Choose the best solution for data archival ( On Premises  Vs Cloud) and best data retrieval strategy (Cold and Hot Retrievals)
  •        Identify all the application technical components like programs, JCL, Databases, Online entries, Scheduler entries, infrastructure used by the application, different access levels required for different users along with all the interfaces and business processes. Raise a change request for the actual decommissioning solution in the execution step. The change request will have all the details of all associated hardware and software's to retire after decommissioning. 

Typical decommissioning solution is prepared from application usage and detailed parameters gathered during portfolio assessment and detailed impact analysis phase. These parameters are

  •         Managing application access for various users and partners
  •         Managing application upstream and downstream interfaces to ensure landscape collaboration
  •         Managing the data exchanges, decision making for archive or dispose
  •        Managing released infrastructure components used by the application to be decommissioned


Step 4: Actual Execution and Realization

In the execution phase, the identified decommissioning solution is implemented for successful completion of the project. The decommissioning of the applications is executed as per the project plan prepared under Solution planning and reports are generated for each component of solution.

Below are some reports generated during the execution phase and are validated after implementation:-

  •         Impact Analysis Report.
  •        Data Scan Report
  •        Data Archiving/Migration/Integration Reports

More coming in my next blog.

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