Host classes in Managed Service for ClickHouse®

The host class determines the computing power allocated for each host in a cluster. When you change the host class for a cluster, all existing hosts change accordingly.

The host class determines the available disk types:

• s1, s2, s3, m2, m3, c3: network-ssd, network-hdd, local-ssd, network-ssd-nonreplicated, network-ssd-io-m3.
• s4a, m4a, c4a: network-ssd, local-ssd, network-ssd-nonreplicated, network-ssd-io-m3.
• s4af, m4af, c4af: network-ssd, network-ssd-nonreplicated, network-ssd-io-m3.
• b1, b2, b3: network-ssd, network-hdd.

For storage size limitations, see Quotas and limits.

The host class affects the Max server memory usage DBMS setting that limits the amount of RAM ClickHouse® can use. To learn more, see Memory management.

Available host classesAvailable host classes

Hosts in Managed Service for ClickHouse® clusters are deployed on Yandex Compute Cloud VMs. You can create these VMs on any platforms Compute Cloud supports. To learn more about the platforms, see Platforms.

The full list of possible host configurations on each platform is provided below.

The available host configurations for each of the platforms depend on the following factors:

• Database management system.
• Processor type.
• Allocated quota.
• Availability zone.

For example, ru-central1-d does not support Intel Broadwell and local SSD storage if Intel Cascade Lake is used.

Configuration types:

• s1, s2, s3, s4a, s4af: Standard configurations with a 4:1 RAM GB to vCPU ratio.
• m2, m3, m4a, m4af: Configurations with an increased RAM GB to vCPU ratio (8:1). These configurations are well suited for clusters with high cache requirements.
• c3, c4a, c4af: Configurations with a reduced RAM GB to vCPU ratio (2:1). These configurations may be useful for clusters with higher processor performance requirements.
• b1, b2, b3: Configurations with a guaranteed vCPU share under 100%. This host class is intended for test workloads. The minimum recommended host configuration for production solutions is two vCPUs with a guaranteed share of 50%.

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