[Yandex Cloud documentation](../../index.md) > [Yandex Managed Service for Sharded PostgreSQL](../index.md) > [Concepts](index.md) > Host classes # Yandex Managed Service for Sharded PostgreSQL host classes The host class determines the computing power allocated for each host in a Managed Service for Sharded PostgreSQL cluster. If a cluster uses standard sharding, changing the host class updates the properties of all previously created hosts. If a cluster uses advanced sharding, the host class is changed separately for hosts with the `ROUTER` and `COORDINATOR` roles. Changing the configuration updates the properties of all previously created hosts. ## Available host classes {#available-flavors} Hosts in Managed Service for Sharded PostgreSQL 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 [this article](../../compute/concepts/vm-platforms.md). The full list of possible host configurations on each platform is provided below. All configurations support two disk types: `network-ssd` and `network-hdd`. The storage size does not depend on the host class. {% note info %} AMD Zen 4 is available to a limited number of users for private testing. To request access to the platform, contact your account manager. Intel Broadwell is not available for clusters with hosts residing in the `ru-central1-d` [availability zone](../../overview/concepts/geo-scope.md). {% endnote %} Configuration types: * **s1**, **s2**, **s3**, and **s4a**: Standard configurations with a 4:1 RAM GB to vCPU ratio. * **m2**, **m3**, and **m4a**: Configurations with an increased RAM GB to vCPU ratio (8:1). These configurations are well suited for clusters with high cache requirements. * **c3** and **c4a**: 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%. {% note info %} Hosts with a guaranteed vCPU share under 50% cannot be used in multi-host clusters. {% endnote %} | Host class name | Number of vCPUs | CPU performance | RAM, GB | Disk
size, GB | |-------------------|----------------|------------------------|---------|----------------------| | **Intel Broadwell** | | b1.medium | 2 | 50% | 4 | 10–512 | | s1.micro | 2 | 100% | 8 | 10–512 | | s1.small | 4 | 100% | 16 | 10–512 | | s1.medium | 8 | 100% | 32 | 10–512 | | s1.large | 16 | 100% | 64 | 10–512 | | s1.xlarge | 32 | 100% | 128 | 10–512 | | **Intel Cascade Lake** | | b2.medium | 2 | 50% | 4 | 10–512 | | m2.micro | 2 | 100% | 16 | 10–512 | | m2.small | 4 | 100% | 32 | 10–512 | | m2.medium | 6 | 100% | 48 | 10–512 | | m2.large | 8 | 100% | 64 | 10–512 | | m2.xlarge | 12 | 100% | 96 | 10–512 | | m2.2xlarge | 16 | 100% | 128 | 10–512 | | m2.3xlarge | 24 | 100% | 192 | 10–512 | | m2.4xlarge | 32 | 100% | 256 | 10–512 | | m2.5xlarge | 40 | 100% | 320 | 10–512 | | m2.6xlarge | 48 | 100% | 384 | 10–512 | | m2.7xlarge | 56 | 100% | 448 | 10–512 | | m2.8xlarge | 64 | 100% | 512 | 10–512 | | s2.micro | 2 | 100% | 8 | 10–512 | | s2.small | 4 | 100% | 16 | 10–512 | | s2.medium | 8 | 100% | 32 | 10–512 | | s2.large | 12 | 100% | 48 | 10–512 | | s2.xlarge | 16 | 100% | 64 | 10–512 | | s2.2xlarge | 24 | 100% | 96 | 10–512 | | s2.3xlarge | 32 | 100% | 128 | 10–512 | | s2.4xlarge | 40 | 100% | 160 | 10–512 | | s2.5xlarge | 48 | 100% | 192 | 10–512 | | s2.6xlarge | 64 | 100% | 256 | 10–512 | | **Intel Ice Lake** | | b3-c1-m4 | 2 | 50% | 4 | 10–512 | | s3-c2-m8 | 2 | 100% | 8 | 10–512 | | s3-c4-m16 | 4 | 100% | 16 | 10–512 | | s3-c8-m32 | 8 | 100% | 32 | 10–512 | | s3-c12-m48 | 12 | 100% | 48 | 10–512 | | s3-c16-m64 | 16 | 100% | 64 | 10–512 | | s3-c24-m96 | 24 | 100% | 96 | 10–512 | | s3-c32-m128 | 32 | 100% | 128 | 10–512 | | s3-c40-m160 | 40 | 100% | 160 | 10–512 | | s3-c48-m192 | 48 | 100% | 192 | 10–512 | | s3-c64-m256 | 64 | 100% | 256 | 10–512 | | s3-c80-m320 | 80 | 100% | 320 | 10–512 | | m3-c2-m16 | 2 | 100% | 16 | 10–512 | | m3-c4-m32 | 4 | 100% | 32 | 10–512 | | m3-c6-m48 | 6 | 100% | 48 | 10–512 | | m3-c8-m64 | 8 | 100% | 64 | 10–512 | | m3-c12-m96 | 12 | 100% | 96 | 10–512 | | m3-c16-m128 | 16 | 100% | 128 | 10–512 | | m3-c24-m192 | 24 | 100% | 192 | 10–512 | | m3-c32-m256 | 32 | 100% | 256 | 10–512 | | m3-c40-m320 | 40 | 100% | 320 | 10–512 | | c3-c2-m4 | 2 | 100% | 4 | 10–512 | | c3-c4-m8 | 4 | 100% | 8 | 10–512 | | c3-c8-m16 | 8 | 100% | 16 | 10–512 | | c3-c12-m24 | 12 | 100% | 24 | 10–512 | | c3-c16-m32 | 16 | 100% | 32 | 10–512 | | c3-c24-m48 | 24 | 100% | 48 | 10–512 | | c3-c32-m64 | 32 | 100% | 64 | 10–512 | | c3-c40-m80 | 40 | 100% | 80 | 10–512 | | c3-c48-m96 | 48 | 100% | 96 | 10–512 | | c3-c64-m128 | 64 | 100% | 128 | 10–512 | | c3-c80-m160 | 80 | 100% | 160 | 10–512 | | c3-c96-m192 | 96 | 100% | 192 | 10–512 | | **AMD Zen 3** | | s4a-c2-m8 | 2 | 100% | 8 | 10–512 | | s4a-c4-m16 | 4 | 100% | 16 | 10–512 | | s4a-c8-m32 | 8 | 100% | 32 | 10–512 | | s4a-c12-m48 | 12 | 100% | 48 | 10–512 | | s4a-c16-m64 | 16 | 100% | 64 | 10–512 | | s4a-c24-m96 | 24 | 100% | 96 | 10–512 | | s4a-c32-128 | 32 | 100% | 128 | 10–512 | | s4a-c40-m160 | 40 | 100% | 160 | 10–512 | | s4a-c48-192 | 48 | 100% | 192 | 10–512 | | s4a-c64-m256 | 64 | 100% | 256 | 10–512 | | s4a-c80-320 | 80 | 100% | 320 | 10–512 | | s4a-c96-m576 | 96 | 100% | 576 | 10–512 | | m4a-c2-m16 | 2 | 100% | 16 | 10–512 | | m4a-c4-m32 | 4 | 100% | 32 | 10–512 | | m4a-c6-m48 | 6 | 100% | 48 | 10–512 | | m4a-c8-m64 | 8 | 100% | 64 | 10–512 | | m4a-c12-m96 | 12 | 100% | 96 | 10–512 | | m4a-c16-m128 | 16 | 100% | 128 | 10–512 | | m4a-c24-m192 | 24 | 100% | 192 | 10–512 | | m4a-c32-m256 | 32 | 100% | 256 | 10–512 | | m4a-c40-m320 | 40 | 100% | 320 | 10–512 | | m4a-c48-m384 | 48 | 100% | 384 | 10–512 | | m4a-c56-448 | 56 | 100% | 448 | 10–512 | | m4a-c64-m512 | 64 | 100% | 512 | 10–512 | | m4a-c80-m640 | 80 | 100% | 640 | 10–512 | | c4a-c2-m4 | 2 | 100% | 4 | 10–512 | | c4a-c4-m8 | 4 | 100% | 8 | 10–512 | | c4a-c8-m16 | 8 | 100% | 16 | 10–512 | | c4a-c12-m24 | 12 | 100% | 24 | 10–512 | | c4a-c16-m32 | 16 | 100% | 32 | 10–512 | | c4a-c24-m48 | 24 | 100% | 48 | 10–512 | | c4a-c32-m64 | 32 | 100% | 64 | 10–512 | | c4a-c40-m80 | 40 | 100% | 80 | 10–512 | | c4a-c48-m96 | 48 | 100% | 96 | 10–512 | | c4a-c64-m128 | 64 | 100% | 128 | 10–512 | | c4a-c80-m160 | 80 | 100% | 160 | 10–512 | | c4a-c96-m192 | 96 | 100% | 192 | 10–512 |