Mainframe Performance & Capacity Administrator – z/OS | Contract | Office Based
We are seeking an experienced Mainframe Performance & Capacity Administrator to support a large-scale IBM z/OS enterprise environment. This is a high-impact contract role focused on performance tuning, capacity planning, and cost optimisation across mission-critical mainframe systems.
You will lead performance and capacity initiatives across complex z/OS, SYSPLEX and PR/SM environments, ensuring optimal utilisation of CPU, memory, DASD and WLM-managed workloads. This role requires deep expertise in RMF, SMF, MXG, MICS, SAS and TMON, along with strong knowledge of MIPS, MSU, 4HRA and soft capping models.
Key Responsibilities
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Analyse RMF and SMF records to diagnose performance issues
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Tune WLM service definitions and optimise workload placement
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Lead capacity forecasting and modelling across enterprise estates
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Support SCRT reporting and MSU cost management
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Optimise zIIP, GP processors and PR/SM configurations
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Provide 24/7 on-call support for critical systems
Essential Skills
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IBM z/OS performance and capacity management
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Strong experience with SMF, RMF, MXG, MICS, SAS or TMON
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Expertise in WLM tuning and SYSPLEX environments
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Proven capacity planning and performance optimisation experience
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Deep understanding of MIPS, MSU, 4HRA and soft capping
Experience within large enterprise, banking, insurance or regulated environments is highly desirable.
This is a senior-level contract opportunity offering strong visibility and ownership within a complex mainframe estate.
Apply now if you are a specialist in z/OS performance tuning and capacity management looking for your next contract challenge
