Senior System Administrator

Alsena; Brussel Hoofdstad; On-site; EUR 70,000 - 110,000; Full time

Job summary

Alsena is seeking an experienced System Administrator (Database Focus) to join an IT infrastructure project in Brussels. The role combines database administration with broader IT infrastructure responsibilities, ensuring availability, security and performance of enterprise databases in a complex international environment.

The ideal candidate will have hands‑on experience with Oracle, Microsoft SQL Server and PostgreSQL, plus on‑prem and Azure cloud environments.

Qualifications

• Masters or Bachelors in CS/IT with 8+ years of relevant experience.
• Proven database administration across Oracle, SQL Server and PostgreSQL.
• Experience in on‑prem and Azure cloud environments.
• Strong security, backup/recovery and DR procedures.
• Excellent documentation and communication in English.

Responsibilities

• Administer, tune and secure Oracle, SQL Server and PostgreSQL databases.
• Manage connectivity, listeners, tablespaces, users and access control.
• Ensure high availability, monitoring, backups and disaster recovery.
• Automate admin tasks with scripts (PowerShell, SQL).
• Collaborate with Windows Server, IIS, AD, Entra ID and Azure DevOps.
• Prepare technical docs and operational reports.

Skills

Oracle

SQL Server

PostgreSQL

Azure

PowerShell

Windows Server

IIS

Active Directory

Education

Master's degree in Computer Science / IT

Bachelor's degree in Computer Science / IT

Tools

Azure Cloud

SQL Server Management Studio

Oracle SQL Developer

Monitoring tools

Job description

We are looking for an experienced System Administrator (Database Focus) to join an IT infrastructure project within a European institution in Brussels.

The ideal candidate will have strong hands‑on experience in database administration, infrastructure operations, performance optimisation and security, with expertise in Oracle, Microsoft SQL Server and PostgreSQL.

This position combines database administration with broader IT infrastructure responsibilities, ensuring the availability, security, reliability and performance of critical database systems in a complex international environment.

Your Role:

• Administer, maintain and optimise Oracle, Microsoft SQL Server and PostgreSQL databases, operating in both on‑premises and Microsoft Azure cloud environments.
• Perform daily database administration tasks, including installation, configuration, patching, performance tuning, monitoring, backup and recovery.
• Manage database connectivity, listeners, tablespaces, user accounts and access permissions.
• Ensure database availability, reliability and performance through proactive monitoring and advanced troubleshooting.
• Support the evolution and improvement of database infrastructure, architectures and hosting platforms.
• Implement database security measures, including system hardening, vulnerability identification and remediation, access control and security auditing.
• Analyse database logs, identify potential security risks and ensure compliance with security requirements.
• Develop and maintain scripts to automate database administration and operational processes.
• Support application owners and users in resolving database‑related issues.
• Contribute to broader system administration activities involving Windows Server, IIS, Active Directory, Microsoft Entra ID and Azure DevOps.
• Assist with certificate renewals, infrastructure troubleshooting and operational problem‑solving.
• Prepare and maintain technical documentation, operational reports and technical presentations.

The Profile We Are Looking For:

We are seeking an experienced, hands‑on IT professional with strong expertise in database administration and infrastructure operations.

The ideal candidate is comfortable managing production databases, troubleshooting complex technical issues and ensuring the security, availability and performance of enterprise database environments.

Key Skills:

Database Administration:

• Strong hands‑on experience with Oracle Database, Microsoft SQL Server and PostgreSQL.
• Experience administering databases in on‑premises and Microsoft Azure cloud environments.
• Database installation, configuration, patching and upgrades.
• Performance monitoring, optimisation and troubleshooting.
• Backup, recovery and disaster recovery procedures.
• High availability and database capacity management.
• Database security, access management and vulnerability remediation.
• Database automation and scripting.

Systems & Infrastructure:

• Windows Server administration.
• Active Directory and Microsoft Entra ID.
• Microsoft Azure infrastructure and services.
• IIS administration.
• Azure DevOps and deployment pipelines.
• Infrastructure monitoring and troubleshooting.
• Scripting and automation using PowerShell, SQL or equivalent technologies.

Desired Qualifications:

• Master's degree in Computer Science, Information Technology or a related field, with at least 8 years of relevant professional experience.
• OR
• Bachelor's degree in Computer Science, Information Technology or a related field, with at least 12 years of relevant professional experience.
• Proven professional experience in database administration and infrastructure operations.
• Strong analytical, troubleshooting and problem‑solving skills.
• Ability to work independently and collaborate effectively with technical teams.
• Excellent written and spoken English.
• Strong communication skills and the ability to produce clear technical documentation.
• Experience working in complex enterprise IT environments.

Additional Information:

• Working environment: International, multicultural and technically complex.

Joining us means contributing to high‑impact international IT projects within a complex and multicultural environment.

You will have the opportunity to work with enterprise‑level database technologies, strengthen your expertise in database administration, cloud infrastructure, security, automation and performance optimisation, and contribute to the reliability and continuous improvement of critical IT systems supporting European institutions.