Senior Database Administrator (remote)

• Operate, scale and safeguard our PostgreSQL, ClickHouse and Elasticsearch clusters, which provide data redundancy across multiple datacenters and form the backbone of our DDoS defense and WAAP platform.
• Design and maintain high-availability and replication topologies, plan failover and disaster-recovery strategies, and ensure data integrity and durability even when an entire datacenter goes offline.
• Own the full schema lifecycle - review and ship versioned migrations and their matching reverts, enforce our SQL coding guidelines, and keep changes safe to roll out across clusters under heavy load.
• Tune performance end to end: query optimization, indexing, partitioning and sharding strategies, and capacity planning for ingest-heavy OLAP workloads (ClickHouse) alongside transactional OLTP workloads (PostgreSQL).
• Integrate and Improve monitoring, alerting and backup automation so issues are caught before they reach our customers, and so recovery is fast, tested and reliable.
• Work closely with our development and operations teams as the go-to expert on data modeling, storage and retrieval, supporting them in complex debugging and troubleshooting tasks.
• Contribute to a performance-critical environment where efficiency, scalability and reliability matter every day., * We live our startup mentality at heart. The professional framework gives us the growth and stability of Link11- founded in 2005. We are still strong today working alongside the founders and the management team.
• We are full of energy, have short decision-making paths and bring changes directly on the way.
• We live a positive, interactive and appreciative working atmosphere in which all employees can contribute.
• We encourage the further development of our employees.
• We are willing to leave our comfort zone for innovation and improvement because we want to be the best in the market.
• We have received several awards for our forward-looking solutions.

Do you have experience in SQL?, * Solid experience administering relational databases in production, with strong expertise in PostgreSQL (replication, high availability, backup/restore, query tuning).

• Hands-on experience with ClickHouse or comparable column-oriented / OLAP databases, including partitioning, MergeTree engines and large-scale ingest.
• Experience operating Elasticsearch (cluster sizing, sharding, index lifecycle management, query and indexing performance).
• Practical experience running databases in clustered, multi-datacenter setups with replication, failover and data redundancy.
• Strong command of SQL and a deep understanding of indexing, query execution plans, partitioning and performance optimization.
• Comprehensive experience with Linux operating systems and a good understanding of networking, storage and how they affect database performance.
• Solid grasp of backup, disaster recovery and monitoring/observability practices for data systems.
• A mindset geared toward sharing knowledge, learning continuously, and contributing to technical discussions.
• Ability to work both independently and collaboratively, while communicating requirements, challenges, and progress clearly to technical and non-technical stakeholders.
• Excellent communication skills in English or German.

• Meet your colleagues at eye level. We are all equal and without barriers.
• Live and develop your strengths in a friendly atmosphere.
• Organise yourself in a flexible working model, because you are more than just your job.
• Lead us to success with your skills.
• Community is the trump card: team events, sundowners, after work parties bring us together (also internationally).
• Taking care of our team doesn't end at the coffee machine or a filled fruit basket!
• Look forward to interesting benefits such as fitness, JobRad, support for daycare fees and much more. We are cooperation partners of national and international associations and authorities.

Link11 is a specialized European IT security provider in the field of cyber-resilience. The global protection solutions of the Cloud Security Platform are fully automated, react in real-time and defend against all attacks, including unknown and new patterns, in under 10 seconds. According to unanimous analyst opinion (Gartner, Frost & Sullivan) Link11 offers the fastest mitigation (TTM) available on the market. To ensure cyber-resilience, web and infrastructure DDoS protection, bot mitigation, API protection, secure DNS, zero touch WAF, secure CDN, and threat intelligence services, among others, ensure holistic and cross-platform hardening of corporate networks and critical applications. International customers can thus concentrate on their business and digital growth. Since the company was founded in 2005, Link11 has received multiple awards for its innovative solutions.