Resource relationships in Managed Service for Redis
Redis is a high-performance DBMS for storing key-value data that runs in RAM. Managed Service for Redis allows you to easily create Redis host clusters with a high level of fault tolerance.
The main entity used in Managed Service for Redis 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 and even different availability regions. You can learn more about Yandex Cloud availability zones here.
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A cluster consisting of three or more hosts supports automatic failover, as each host can take the cluster's primary replica role.
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A cluster of one or two hosts is cheaper, but it does not guarantee fault tolerance.
When creating a cluster, specify:
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Host class: VM template for deploying the cluster hosts. For a list of available host classes and their specs, see Host classes.
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Environment: Environment where the cluster will be deployed:
PRODUCTION: For stable versions of your apps.PRESTABLE: For testing purposes. The prestable environment is similar to the production environment and likewise covered by the SLA, but it is the first to get new functionalities, improvements, and bug fixes. In the prestable environment, you can test compatibility of new versions with your application.
Note
The amount of memory allocated to a host is also determined by the maxmemory configuration parameter for Redis hosts; the maximum amount of data is 75% of the available memory. For example, for a host class with 8 GB RAM, the maxmemory value will be 6 GB.
A cluster created in a folder can be accessed by all VMs connected to the same cloud network. For more information about networking, see the Virtual Private Cloud documentation.
Alert
The service can automatically access the system and diagnostic information of your databases to build monitoring charts and maintain your cluster health. The service never queries or uses the data you saved to the database.