Salary: £54,000 - 60,000 per year Requirements: IBM z/OS performance and capacity management Strong experience with SMF, RMF, MXG, MICS, SAS or TMON Expertise in WLM tuning and SYSPLEX environments Proven capacity planning and performance optimisation experience Deep understanding of MIPS, MSU, 4HRA and soft capping Experience within large enterprise, banking, insurance or regulated environments is highly desirable Responsibilities: Analyse RMF and SMF records to diagnose performance issues Tune WLM service definitions and optimise workload placement Lead capacity forecasting and modelling across enterprise estates Support SCRT reporting and MSU cost management Optimise zIIP, GP processors and PR/SM configurations Provide 24/7 on-call support for critical systems Technologies: IBM Support SAS More: We are seeking an experienced Mainframe Performance & Capacity Administrator to support our large-scale IBM z/OS enterprise environment. This high-impact contract role focuses on performance tuning, capacity planning, and cost optimisation across mission-critical mainframe systems. This is a senior-level opportunity offering strong visibility and ownership within a complex mainframe estate. last updated 7 week of 2026