Sr. Engineer System administrator Toronto, ON, CA

OnX; Toronto; Hybrid; CAD 62,000 - 82,000; Full time

Benefits offered by this job

Competitive compensation and benefits

Professional development and certifi c.

Flexible work options

Job summary

OnX is seeking a Senior Systems Administrator to join our Infrastructure Services team. You will manage enterprise Windows and Linux servers, with cloud exposure across AWS and Azure, focusing on uptime, security, and efficiency.

You will mentor junior staff, document procedures, and collaborate across networking, security, and application teams to deliver scalable IT infrastructure in Canada.

Qualifications

• Bachelor’s degree in Computer Science, IT, Engineering, Telecommunications, or a related technical discipline.
• 6+ years of overall IT infrastructure experience and 5+ years hands-on systems administration in enterprise environments.
• Experience maintaining Windows and Linux server environments, with cloud familiarity a plus.

Responsibilities

• Administer and support enterprise Windows and Linux server environments.
• Perform OS installation, configuration, patching, upgrades, and lifecycle management.
• Monitor system health, performance, and availability; proactively resolve issues.
• Implement infrastructure improvements for scalability, resiliency, and efficiency.
• Manage security baselines, vulnerability remediation, and hardening activities.
• Support cloud-based infrastructure across AWS and Azure environments.
• Automate operations using scripting and automation tools; collaborate with teams to deliver integrated solutions.
• Perform capacity planning and maintain documentation and knowledge articles.

Skills

Linux Administration

Windows Server Administration

Unix Administration

Infrastructure Monitoring

Patching & Maintenance

Performance Optimization

Security Hardening

Server Lifecycle Management

Python

Bash Scripting

PowerShell

Education

Bachelor’s degree in Computer Science / IT / Engineering / Telecommunications

Tools

AWS Administration

Microsoft Azure Administration

Citrix XenServer

Sun Solaris

AS/400

WSUS

Job description

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

• 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.

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.

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.