Senior zOS Systems Engineer

At BBH, Partnership is more than a form of ownership—it’s our approach to business and relationships. We know that supporting your professional and personal goals is the best way to help our clients and advance our business. We take that responsibility seriously. With a 200-year legacy and a shared passion for what’s next, this is the right place to build a fulfilling career.

The Operating System Support MVS (OSS MVS) group is responsible for the enterprise z/OS platform supporting mission‑critical production and test workloads. The Senior z/OS Systems Engineer serves as the technical authority for the z/OS environment, with accountability for platform architecture, resiliency, performance, and long‑term sustainability. This role goes beyond traditional system programming execution, and include performance tuning and ensuring the overall health of the environment.

The Senior z/OS Engineer is involved in design decisions, engineering standards, and modernization initiatives, while providing expert guidance to application development teams, infrastructure partners, and data center operations. The position reports to the OSS MVS Manager and plays a key role in ensuring the stability, scalability, and evolution of the mainframe platform.

• Own the architecture, design, and engineering standards for the enterprise z/OS platform, including sysplex design, availability, performance, and recoverability.
• Serve as an escalation point for complex z/OS, JES, sysplex, and program product issues.
• Define and maintain best practices for operating system configuration, resiliency, and performance optimization.
• Lead capacity planning, performance analysis, and tuning strategies aligned with business requirements.
• Lead z/OS operating system installation and customization using the IBM Server Pac process.
• Oversee installation, customization, and lifecycle management of IBM program products such as (GRS, RMM).
• Plan and execute z/OS upgrades, refreshes, and modernization initiatives, ensuring minimal risk and business disruption.
• Apply operating system and program product maintenance on a regular and controlled basis.
• Monitor system activity and analyze performance data using industry‑standard tools.
• Provide expert recommendations to application teams to improve workload efficiency and system throughput.
• Own and continuously improve disaster recovery architecture and procedures, ensuring recoverability objectives are met.
• Partner with infrastructure teams to ensure end‑to‑end availability across compute, storage, and network layers.
• Provide technical leadership and mentorship to system programmers and junior engineers.
• Act as a trusted advisor to application development, infrastructure, and security teams.
• Interface effectively with all areas affected by major system changes, including business stakeholders and vendor partners.
• Represent the z/OS platform in architecture reviews and enterprise technology initiatives.

• 10+ years of experience as a z/OS Systems Engineer or System Programmer, including significant experience in large‑scale Parallel Sysplex environments.
• Deep expertise in z/OS architecture, internals, operations, and recovery scenarios.
• Proven experience leading complex, enterprise‑level z/OS initiatives and acting as a technical authority.
• Extensive experience installing and customizing IBM program products; GRS and RMM experience preferred.
• Strong working knowledge of major subsystems, including CICS, Db2, and MQ.
• Hands‑on experience with I/O configuration using HCD.
• Advanced debugging and problem‑determination skills across OS and program products.
• Strong experience with RACF; familiarity with zSecure is a plus.
• Experience writing user exits and automation…