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Frequently Asked Questions
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Frequently Asked Questions

What are Cloud Databases⁠

This is a service of the Selectel cloud platform. It allows you to quickly deploy resilient database clusters in the cloud with PITR recovery.

Setup, configuration, infrastructure maintenance, security and fault tolerance, backups and scaling are performed on the Selectel side.

What is a database cluster⁠

This is one or more database nodes (servers) between which replication is configured.

The main server of the cluster is the master node. Replicas — exact copies of the master — can be added to the cluster. If the master becomes unavailable, one of the replicas takes over the role of the master and a new replica is created in its place (the address of the master node changes). Such a cluster is reliable and is used to support applications.

How to realize that the cluster has been created and everything is working⁠

A cluster is successfully created and running if the cluster itself and all nodes have ACTIVE status.

Can the cluster settings be changed after the cluster is created⁠

Once the cluster is created, you can modify it:

You cannot change the subnet to which the cluster is connected.

What can go wrong in a cluster operation⁠

In a failover cluster, one of the nodes may become unavailable. This means that a node has not sent information that it is in ACTIVE status for a minute. In this case, we will remove the existing node and replace it with another node.

If a cluster consists only of a master node and it becomes unavailable, the cluster also becomes temporarily unavailable until a new master is created to replace the inactive master. In this case, the databases are not lost, but become unavailable for some time. You can contact technical support to solve the problem or restore the cluster from backup — PostgreSQL, PostgreSQL for 1C, PostgreSQL TimescaleDB, MySQL sync, MySQL semi-sync, Redis.

What are the restrictions⁠

Can be created as part of a single project:

  • 10000 databases within all clusters;
  • 1,000 database users.

The number of clusters is limited by quotas for cluster resources — DBaaS vCPU, RAM and local disk. You can increase the project limits and quotas.

A cluster can be created in private and public subnets. You can connect public IP addresses for nodes in the private subnet.

How much does it cost to use the Cloud Databases service⁠

Prices for cloud database resources can be viewed at selectel.ru.

Is it possible to fine-tune the DBMS⁠

The default database settings are picked up and depend on the selected cluster node configuration.

You can configure PostgreSQL, PostgreSQL for 1C, PostgreSQL TimescaleDB, MySQL sync, MySQL semi-sync and Kafka on your own.

What happens if the cluster node disk runs out of space⁠

If the cluster disk is 80% full, a notification will appear in the dashboard and will be sent to the Account Owner's email and those users subscribed to the "Services and Services" notification category.

If the cluster disk is 95% full or more, the cluster will go to DISK_FULL status and will be read-only. To make the cluster read-write, clear the disk or scale the cluster PostgreSQL, PostgreSQL for 1C, PostgreSQL TimescaleDB, MySQL sync, MySQL semi-sync, Redis and Kafka and select a configuration with a larger disk size.

Why we do not provide the superuser role⁠

A superuser can have full control over the database and server, such as changing configurations, managing users, and executing critical commands. Providing this role can lead to security breaches, data leaks, and system failures, so we do not provide the superuser role in the Cloud Database product. If you need to perform actions that can only be performed by a superuser, create a ticket.