Sr. Engineer System administrator

Toronto, ON
On-site
Posted Oct 8, 2026
1 position

$62,000–$82,000 / year

Opens LinkedIn

Employment type: Full-time
Experience level: Senior · 5+ years
Minimum education: Bachelor’s degree
Posting language: English
Working hours: 40 hours per week
Seniority: Associate

Job summary

Administer, maintain, secure, and optimize enterprise Windows and Linux server environments, including operating system lifecycle management, monitoring, troubleshooting, and cloud infrastructure support across AWS and Azure. Improve infrastructure resilience and efficiency through automation, capacity planning, documentation, cross-team collaboration, and mentoring junior team members.

Job details

OnX is a leading Canadian technology solutions provider helping organizations modernize, secure, and optimize their IT environments. We partner with clients across industries to deliver innovative infrastructure, cloud, security, and managed services solutions that drive business success. We are seeking a highly skilled Senior Systems Administrator to join our Infrastructure Services team. This role is ideal for a hands-on technical professional who thrives in complex enterprise environments and enjoys managing mission-critical server infrastructure across Windows, Linux, and cloud platforms. What You'll Do As a Senior Systems Administrator, you will be responsible for maintaining, optimizing, and securing enterprise server environments while ensuring the highest levels of performance, availability, and compliance. Key Responsibilities Administer and support enterprise Windows and Linux server environments. Perform operating system installation, configuration, patching, upgrades, and lifecycle management. Monitor system health, performance, and availability, proactively identifying and resolving issues. Implement infrastructure improvements that enhance scalability, resiliency, and operational efficiency. Manage enterprise security baselines, vulnerability remediation efforts, and system hardening activities. Support cloud-based infrastructure across AWS and Microsoft Azure environments. Automate operational processes using scripting and automation tools. Collaborate with networking, security, application, and cloud teams to deliver integrated technology solutions. Perform capacity planning and growth forecasting for server and compute environments. Maintain technical documentation, operational procedures, and knowledge articles. Mentor junior team members and provide technical guidance on infrastructure best practices. Required Qualifications Education Bachelor's degree in Computer Science, Information Technology, Engineering, Telecommunications, or a related technical discipline. Experience 6+ years of overall IT infrastructure experience. 5+ years of hands-on systems administration experience in enterprise environments. Technical Skills Required Linux Administration Windows Server Administration (Wintel) Unix Administration Infrastructure Monitoring and Troubleshooting Operating System Patching and Maintenance Performance Optimization Security Hardening and Compliance Server Lifecycle Management Preferred AWS Administration Microsoft Azure Administration Citrix XenServer Sun Solaris AS/400 WSUS Python Bash Scripting PowerShell Desired Competencies Infrastructure Provisioning & Configuration Management Performance Monitoring & Optimization Virtualization Technologies Automation & Scripting Security & Compliance Management Capacity Planning & Resource Management Strong Problem-Solving Skills Effective Communication Ownership and Accountability Collaboration and Teamwork Customer-Focused Mindset Success Measures In this role, success will be measured through: Infrastructure uptime and SLA achievement Reduced incident resolution times (MTTR) Security compliance and vulnerability remediation performance Increased automation and operational efficiency Adherence to infrastructure standards and governance practices Why Join OnX? Work with modern infrastructure and cloud technologies. Collaborate with experienced technology professionals across Canada. Gain exposure to enterprise-scale environments and strategic initiatives. Competitive compensation and benefits package. Professional development and certification support. Flexible work options depending on role requirements. CAD $62,000 – $82,000 base salary (not including bonus or commission) The compensation range in this posting reflects the Company’s good‑faith estimate at the time of publication. The applicable base pay range for any individual will be determined based on the candidate’s designated primary work location as well as factors including role scope and responsibilities, required qualifications, and the individual’s experience, education, skills, knowledge, and performance. Certain positions may also be eligible for additional compensation such as discretionary merit increases, bonuses, or sales‑based variable compensation in accordance with applicable plans and role requirements. Diversity & Inclusion OnX is an equal opportunity employer committed to creating an inclusive environment for all employees. We celebrate diversity and are dedicated to fostering a workplace where everyone can thrive regardless of race, religion, gender, age, disability, sexual orientation, or any other protected characteristic.

What you’ll do

Requirements

Requires a bachelor's degree in Computer Science, Information Technology, Engineering, Telecommunications, or a related technical discipline, along with at least six years of overall IT infrastructure experience. Candidates must have at least five years of hands-on enterprise systems administration experience and skills in Linux, Windows Server, Unix, monitoring, patching, performance optimization, security, and server lifecycle management.