Position title : Sr. Systems Administrator, Linux & Unix

Location : Downtown Montreal (hybrid)

Reports to : Manager, Systems Administration

The mission of the Infrastructure and Operations, Centre of Expertise group is to make Domtar a world-class customer focused IT organization and effective business partner; become a reference for operating efficiency and be an IT employer of choice.

The Senior System Administrator is responsible for the design, implementation, operation, and stability of enterprise Linux/UNIX platforms supporting mission‑critical business services. This role provides advanced technical leadership, performs complex troubleshooting, and ensures systems meet availability, performance, security, and compliance requirements.

The position works closely with architecture, security, networking, storage, and application teams and acts as a senior escalation point for operational issues. <...