Sr. Administrator Unix/Linux

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.

Job Responsibilities/Accountabilities:

Platform Administration

• Install, configure, patch, and maintain Linux/UNIX operating systems (e.g., RHEL, Oracle Linux, HP-UX)

• Administer physical, virtual, and cloud‑based servers

• Manage system lifecycle activities including builds, upgrades, and decommissioning

• Perform capacity planning and performance tuning

Availability, Reliability & Operations

• Ensure high availability, resiliency, and recoverability of systems

• Implement and maintain monitoring, alerting, and logging solutions

• Participate in on‑call rotations and lead resolution of complex incidents

• Support disaster recovery planning, testing, and execution

Security & Compliance

• Apply OS hardening standards and security baselines

• Manage access controls, privileged access, and auditing

• Support vulnerability remediation and security incident response

• Ensure systems comply with internal standards and regulatory frameworks (e.g., NIST, ISO)

Automation & Tooling

• Develop and maintain automation using shell scripting, Python, or configuration management tools (e.g., Ansible, Puppet, Chef)

• Improve build standardization and reduce manual operational effort

• Contribute to CI/CD or infrastructure‑as‑code initiatives where applicable

Storage, Backup & Networking

• Integrate systems with enterprise storage and backup platforms

• Troubleshoot network‑related issues (DNS, TCP/IP, NFS, firewalls)

• Coordinate with storage and network teams on design and operations

Leadership & Collaboration

• Act as senior technical escalation point for system administration issues

• Mentor junior administrators and provide technical guidance

• Participate in architecture reviews and infrastructure design discussions

• Produce and maintain technical documentation and operational runbooks

Critical Competencies :

• Proven skills of change management;

• Good knowledge of the stages of concept proof and pilot project;

• Excellent problem solving and analysis skills;

• Strong communications skills and bilingual in both English* and French (written and spoken) ;

• Strong technical documentation skills in both English* and French;

• Ability to create and define metrics that accurately reflects the current state of an infrastructure.

(*) This is required since as part of this function, you will have to intervene with customers, partners and/or our American subsidiaries on a recurring basis, both orally and in writing.

Required Qualifications/Professional Experiences:

• University degree with a major in IT or equivalent work experience;

• Minimum of 7 years of relevant experience.

Preferred Qualifications/Professional Experiences/Years of Experience:

• Expert knowledge of the Linux (RHEL) & Unix (HP-UX) Operating Systems.

• Advanced knowledge of the Server platforms, (ESX), (HP-UX), (ITANIUM);

• Advanced knowledge of Cloud and Hyperconverged Infrastructures;

• Good knowledge of Backup and Storage;

• Advanced knowledge or the clustering technologies;

• Advanced knowledge of monitoring processes and management tools (for example Red Hat Satellite, Ansible or SolarWinds);

• Strong security awareness;

• Strong scripting skills;

• General ITIL knowledge;

• Strong knowledge of DR (Disaster Recovery), for SAP, Oracle and VMware environments, would be an asset;

• RHEL, Linux, HP-UX, UNIX certifications are a definite asset.

Domtar is an equal opportunity employer. We invite women, Aboriginal peoples, persons with disabilities and members of visible minorities to apply.

Our offer:

• A downtown location (Place des Arts metro);

• A modern and spacious environment;

• A flexible insurance plan (life, medical, dental);

• An employee assistance program;

• A childcare center on location;

• Competitive compensation, including annual bonus plan;

• A pension plan with matching company contributions;

• Employer-paid development and continuing education.

About Domtar :

Domtar makes products that people around the world rely on every day.

Serving more than 50 countries, we are a leading provider of a wide variety of fiber-based products including communication, specialty and packaging papers, market pulp and airlaid nonwovens. We make our products at manufacturing and converting facilities in the U.S. and Canada, with a focus on safety, quality, and sustainability.

Through our values of agility, caring and innovation, we constantly find better ways to serve our customers, support our employees and strengthen our communities.

Domtar’s principal executive office is in Fort Mill, South Carolina and Domtar is part of the Paper Excellence group of companies. To learn more, visit