At CERN, the European Organization for Nuclear Research, physicists and engineers are probing the fundamental structure of the universe. Using the world's largest and most complex scientific instruments, they study the basic constituents of matter - fundamental particles that are made to collide together at close to the speed of light. The process gives physicists clues about how particles interact, and provides insights into the fundamental laws of nature. 

Introduction

Work with us to evolve the CERN data storage systems used at the Large Hadron Collider (LHC) and at its international partners. CERN is the birthplace of the World Wide Web and one of the world’s leading laboratories for particle physics. Join the Storage and Data Management Group in CERN’s IT Department as a Software Engineer for a unique challenge as the next step in your career. CERN, take part!

The CERN IT Storage and Data Management group operates the core services used by both LHC and non-LHC experiments for data collection, archival, reconstruction, analysis, and global distribution via the Worldwide LHC Computing Grid.

As a Ceph Software Engineer, you will contribute to the design, evolution, and operation of large-scale distributed critical storage services for the CERN cloud and computing infrastructures. You will work hands-on with Ceph-based block, object, and filesystem solutions (including CephFS and NFS integrations), ensuring high availability, performance, and resilience across multi-datacenter environments. Your role will involve troubleshooting complex system-wide issues, optimising storage architectures for demanding workloads such as HPC and AI/ML, and continuously improving automation, deployment, and observability, aligned with modern DevOps practices.

Leveraging strong Linux expertise and systems programming skills (e.g., C/C++, Go, or Rust) you will help evolve the distributed storage technology, while maintaining robust, scalable and secure systems. 

Functions

• Co-lead management and operations of distributed disk storage, block, object and filesystem services based on mainstream open-source technologies (Ceph, NFS).
• Participate in the evolution of architecture and design of storage services for CERN cloud and compute infrastructure, as well as core business applications (physics data processing, ML/AI, HPC use-cases).
• Integrate, troubleshoot and maintain distributed disk storage systems at scale, across multiple availability zones and data centres.
• Contribute to documentation, development, optimisation and further automation of storage services.
• Contribute to change management, incident response, and user support.
• Liaise with key stakeholders inside and outside of the IT department.

Master's degree or equivalent relevant experience in the field of Computer Science or a related field.

Experience:

• Deep understanding of Linux and architecture of storage and filesystems (e.g. NFS, CephFS), including high availability and failure-domain.
• Knowledge of POSIX permissions model, POSIX ACLs and inheritance, and authentication/authorisation concepts (CephX, Kerberos for NFS).
• Proficiency in at least one systems programming language, ideally C/C++, or other high-performance language (e.g. Rust, Golang).
• Good knowledge of scripting languages (e.g. Python, shell) to automate deployment and testing is also required.
• Solid debugging skills for troubleshooting of complex distributed environments and performance tuning.
• Experience in diagnosing complex, system-wide issues which span hardware, network, and software layers.
• DevOps skills (CI/CD, Gitlab, containerisation), monitoring, and system observability (Prometheus, Grafana, or similar).
• Strong collaboration and communication skills to work effectively with multiple cross-functional teams, including infrastructure, application, and end-user communities.

Nice-to-have Skills

• Familiarity with NFS-Ganesha.
• Familiarity with rsync/rclone, snapshots, snapshot-based and incremental replication and filesystem-native migration tooling.
• Familiarity with inotify for change tracking, bind mounts, and Linux VFS semantics.

Technical competencies:

• Design of storage systems.
• Development of application software.
• Knowledge of programming techniques and languages.
• Knowledge of storage technologies.
• Operation and maintenance (preventive and corrective) of storage systems.

Behavioural competencies:

• Achieving Results: delivering prompt and efficient service taking into account customer needs.
• Demonstrating Flexibility: readily absorbing new techniques and working practices; proposing new or improved ways of working.
• Solving Problems: seeking and integrating other points of view when tackling an issue; consulting experts in the field and undertaking benchmarking.
• Working in Teams: building and maintaining constructive and effective work relationships.
• Learning and Sharing Knowledge: seeking feedback from colleagues and other stakeholders about ways of increasing competence.

Language skills:

Spoken and written English, with a commitment to learn French.

Eligibility and closing date:

Diversity has been an integral part of CERN's mission since its foundation and is an established value of the Organization. Employing a diverse workforce is central to our success. We welcome applications from all Member States and Associate Member States.

This vacancy will be filled as soon as possible, and applications should normally reach us no later than 27.05.2026 at 23:59 CEST.

Employment Conditions

Contract type: Limited duration contract (5 years). Subject to certain conditions, holders of limited-duration contracts may apply for an indefinite position.

Working Hours: 40 hours per week

Job Flexibility: Hybrid

This position involves:

• Work during nights, Sundays and official holidays, when required by the needs of the Organization.
• Stand-by duty, when required by the needs of the Organization.

Job grade: 6-7

Job reference: IT-SD-GSS-2026-96-LD

Field of work: Software Engineering and IT

Benchmark Job Title: Computing Engineer

Global Benefits

• A competitive salary (tax free), increasing in line with your years of relevant experience.
• 30 days of paid leave per year plus 2 weeks annual closure.
• Coverage by CERN’s comprehensive health insurance scheme (for yourself, your spouse and children), and membership of the CERN Pension Fund.
• Family, child and infant monthly allowances depending on your individual circumstances.
• A relocation package (installation grant, removal, travel expenses) depending on your individual circumstances.
• Possibility to extend your contract up to 8 years + eligibility for indefinite contract tenure.

Overview of CERN - Discover a world where the impossible is made possible!

At CERN, the European Organization for Nuclear Research, we are pushing the frontiers of science and technology. Our groundbreaking work brings together not only physicists but also a diverse range of professionals from engineering, technical, scientific, and administrative fields. Together, we foster an environment where innovation and collaboration thrive.

Every day, we face exciting new challenges and opportunities to contribute to cutting-edge research that shapes our understanding of the universe. We meet these challenges through the diverse perspectives within our teams, ensuring every contribution is valued and driving our shared sense of inclusion and purpose. Diversity is a core value of CERN since its foundation, and it remains central to our mission and continued success.

If you are ready to be part of a dynamic, inclusive community pushing the boundaries of knowledge, CERN is the place where your curiosity and skills can thrive. Be part of our mission to uncover what lies at the heart of the universe! TAKE PART!

More information about us, here: careers.cern