Database Engineer

The role

You will build and run the data layer including ClickHouse, MooseFS, SeaweedFS, TiDB, and Elasticsearch clusters. You will write code, ship it, and manage storage and query features across 1,200 servers.

What you will do

• Build storage and query features in ClickHouse
• Keep up with upstream ClickHouse LTS releases and ship releases
• Make MooseFS and SeaweedFS highly available and durable
• Find performance problems in production profiles and fix them in the code
• Trace data corruption to its root cause and repair damaged data
• Roll out releases and storage migrations across three regions without downtime
• Run and tune TiDB, TiKV, TiCDC and Elasticsearch
• Check risky designs with TLA+ and fault injection
• Automate repetitive tasks with watchdogs, balancers and dashboards
• Build an SRE agent to watch database clusters and propose fixes

Required qualifications

• Write strong C++, C and Rust
• Can work in Go
• Work in codebases of millions of lines
• Know database storage engines deeply: merges or compaction, replication logs, query execution
• Understand distributed consensus (Raft or Paxos)
• Know Linux storage internals: page cache, fsync, FUSE, file systems, and how NVMe and HDDs behave
• Have run databases or storage on hundreds of nodes
• Led recovery when an incident hit
• Debug with gdb, perf and sanitizers
• Measure a change on production data before calling it a win

Nice to have

• Contributions to an open-source database or file system
• OCaml
• Puppet or a similar configuration management tool

About the company

Ahrefs helps marketers get their brands found in search, in AI answers and on social. The Database team owns databases and storage end to end, from source code to production.