Migrating to ClickHouse Cloud in just three months with no downtime: A 120 terabyte data journey and its benefits

Last year, we realized our existing technical solution no longer met the growing needs of our company. It was clear that a large-scale infrastructure overhaul was necessary, as our technical debt was becoming unmanageable.

We had been using ClickHouse for years, so exploring ClickHouse Cloud on AWS made sense. 

The challenge was migrating a 120 TB database without causing any downtime in our analytics and ensuring a seamless transition. We opted for a “full duplication,” verification, and atomic switchover approach to achieve this.

In this article, I’ll detail how the migration went, the challenges we faced, and the advantages we gained.

Spoiler: Not only did we manage the migration successfully, but we also experienced numerous positive outcomes. The final cost of service after moving to the cloud remained comparable to what it was before. Additionally, we freed up half the time of two engineers, saved a lot of stress, and shifted our focus from maintenance to creation and more interesting tasks.