Independently administering and optimizing production server infrastructure involving Windows Server, directory services, virtualization, compute, storage or storage area network resources, and backup and recovery capabilities; 2. Diagnosing and resolving complex or recurring infrastructure problems involving interactions among multiple systems components using logs, monitoring information, performance data, or other technical evidence to identify root causes and corrective actions; 3. Evaluating and implementing infrastructure security requirements, including system hardening, privileged-access controls, security patching, or vulnerability remediation, while considering operational impacts and system dependencies; and 4. Planning and coordinating major infrastructure upgrades, migrations, system replacements, capacity changes, or other significant production changes and developing or refining technical approaches to address complex systems administration requirements. Administering Windows Server systems and related directory services, including configuration, patching, account or permission administration, performance monitoring, and troubleshooting; 2. Administering virtualized server environments and supporting compute, storage, storage area network, or backup and recovery infrastructure; 3. Diagnosing and resolving production infrastructure problems involving interactions among server operating systems, directory services, virtualization, compute, storage, backup and recovery, or supported applications; and 4. Implementing system security and lifecycle activities such as system hardening, privileged-access controls, security patching, vulnerability remediation, upgrades, migrations, or significant configuration changes.