Hardware Requirements

ClickHouse

ClickHouse will use all available hardware to maximize performance. So the more hardware - the better. As of this publication, the hardware requirements are:

• Minimum Hardware: 4-core CPU with support of SSE4.2, 16 Gb RAM, 1Tb HDD.
  • Recommended for development and staging environments.
  • SSE4.2 is required, and going below 4 Gb of RAM is not recommended.
• Recommended Hardware: >=16-cores, >=64Gb RAM, HDD-raid or SSD.
  • For processing up to hundreds of millions / billions of rows.

For clouds: disk throughput is the more important factor compared to IOPS. Be aware of burst / baseline disk speed difference.

See also: https://clickhouse.tech/benchmark/hardware/

Zookeeper

Zookeeper requires separate servers from those used for ClickHouse. Zookeeper has poor performance when installed on the same node as ClickHouse.

Hardware Requirements for Zookeeper:

• Fast disk speed (ideally NVMe, 128Gb should be enough).
• Any modern CPU (one core, better 2)
• 4Gb of RAM

For clouds - be careful with burstable network disks (like gp2 on aws): you may need up to 1000 IOPs on the disk for on a long run, so gp3 with 3000 IOPs baseline is a better choice.

The number of Zookeeper instances depends on the environment:

• Production: 3 is an optimal number of zookeeper instances.
• Development and Staging: 1 zookeeper instance is sufficient.

See also:

• https://docs.altinity.com/operationsguide/clickhouse-zookeeper/
• altinity-kb-proper-setup
• zookeeper-monitoring

ClickHouse Hardware Configuration

Configure the servers according to those recommendations the ClickHouse Usage Recommendations.

Test Your Hardware

Be sure to test the following:

• RAM speed.
• Network speed.
• Storage speed.

It’s better to find any performance issues before installing ClickHouse.