Presentation
Tranclass: Leveraging z/OS XCF for Cooperative Workload Isolation Across Distributed Transaction Managers at Itau Unibanco
Event Type
Technical Session
Business Continuity/Disaster Recovery
Languages, API's and Framework
Operations Management and Automation
Performance and Capacity Management
Security and Compliance
z/OS Systems Programming
Intermediate
Ensure High Availability and Disaster Recovery
TimeMonday, August 179:45am - 10:05am EDT
LocationRoom 301
DescriptionAs Itau Unibanco modernizes business services to the public cloud, new high-volume coexistence transactions were introduced to maintain data compatibility between mainframe and cloud environments. These transactions generate heavy concurrency on shared database records, causing queuing that exhausts available processing TCBs in the proprietary transaction monitor infrastructure. In critical scenarios, monitors trigger auto-disconnection, cascading impact across the fleet since each monitor instance serves a dedicated pool of bank branches.
We developed Tranclass, a transaction classification mechanism that partitions processing capacity into isolated pools. Infrastructure configuration tables map each transaction to a named class and define dedicated TCB pools per class. When reception TCBs receive a transaction, they resolve the class and route work to the corresponding pool, ensuring that contention in one class cannot starve processing capacity for others.
The key innovation is the use of z/OS Cross-System Coupling Facility (XCF) to build a cooperative, real-time signaling protocol between monitor instances distributed across multiple LPARs. When a monitor detects that a transaction class has exhausted its dedicated TCB pool, it broadcasts a structured XCF group message containing the monitor identity, an action signal, and the affected class name. Receiving monitors update in-memory status areas and their routing functions dynamically redirect traffic away from the impacted instance. When capacity recovers, a normalization signal restores traffic across the fleet.
This session presents the Tranclass architecture, the XCF-based inter-monitor signaling protocol, production deployment results, and lessons from five years of development in collaboration with IBM.
We developed Tranclass, a transaction classification mechanism that partitions processing capacity into isolated pools. Infrastructure configuration tables map each transaction to a named class and define dedicated TCB pools per class. When reception TCBs receive a transaction, they resolve the class and route work to the corresponding pool, ensuring that contention in one class cannot starve processing capacity for others.
The key innovation is the use of z/OS Cross-System Coupling Facility (XCF) to build a cooperative, real-time signaling protocol between monitor instances distributed across multiple LPARs. When a monitor detects that a transaction class has exhausted its dedicated TCB pool, it broadcasts a structured XCF group message containing the monitor identity, an action signal, and the affected class name. Receiving monitors update in-memory status areas and their routing functions dynamically redirect traffic away from the impacted instance. When capacity recovers, a normalization signal restores traffic across the fleet.
This session presents the Tranclass architecture, the XCF-based inter-monitor signaling protocol, production deployment results, and lessons from five years of development in collaboration with IBM.