Mainframe Modernization Testing
Mainframe Modernization Testing (Banking Core Systems)
Technical Deep Dive
The project involved migrating a 40-year-old COBOL/DB2-based transaction processing system (TPS) to a hybrid cloud environment. We implemented:
- Zowe Framework for mainframe DevOps pipelines
- Micro Focus Enterprise Server for x86 emulation
- GoldenGate for real-time data replication
- Custom ANSI SQL wrappers for DB2 isolation
Critical test components included:
- CICS transaction verification using IBM Rational Test Workbench
- VSAM file validation with binary comparison tools
- Batch job timing tests (JCL schedules)
graph LR
A[Legacy TPS] –> B{Test Gateway}
B –> C[Cloud TPS]B –> D[Mainframe TPS]C & D –> E[Comparison Engine]
Data-Rich Results
| Metric | Pre-Migration | Post-Migration |
|---|---|---|
| Batch Window | 6.8 hours | 3.2 hours |
| Peak TPS | 1,250 | 2,400 |
| COBOL Compile Time | 47 min | 8 min |
Unexpected Findings & Mitigations
Optimization Statistics
- Discovery: DB2 NULL handling differed in cloud vs mainframe
- Fix: Implemented schema-level default value mapping
2. Discovery: EBCDIC-to-ASCII conversion corrupted check digits
- Fix: Created custom translation tables for financial data
