Relationship between service resources

The main entity used in Managed Service for SQL Server is a database cluster.

Each cluster consists of one or more database hosts, which are virtual machines with DBMS servers deployed on them. Cluster hosts may reside in different availability zones. More about the geo scope of Yandex.Cloud.

• A cluster consisting of multiple hosts has automatic failover, because the hosts can take over each other's functions as the cluster's primary replica.

• A single-host cluster is cheaper, but it doesn't guarantee fault tolerance.

When creating a cluster, specify:

• Host class: A VM template for deploying the cluster hosts. For a list of available host classes and their characteristics, see Host classes.

• Environment: The environment where the cluster will be deployed:

  • PRODUCTION: For stable versions of your apps.
  • PRESTABLE: For testing, including the Managed Service for SQL Server service itself. The Prestable environment is first updated with new features, improvements, and bug fixes. However, not every update ensures backward compatibility.

• SQL Server version.

  Managed Service for SQL Server clusters support 2016 ServicePack 2 for the following editions:

  • Standard Edition.

    This edition is only available for single-host clusters.

  • Enterprise Edition.

  For the full list of limitations imposed by Managed Service for SQL Server on the clusters of these editions, see Quotas and limits.

  For more information about editions, see the documentation for SQL Server.

A database cluster created in a folder can be accessed by all VM instances connected to the same cloud network. Learn more about networking.