Backups in ClickHouse®

The ClickHouse® provides automatic and manual backups. A backup is automatically created once a day, approximately at 1 a.m. according to your timezone.

Note

Backups have the following temporary restrictions:

  • At the moment, you can create backups only for specific ClickHouse® shards. The functionality that allows creating backups for clusters is currently under development.

  • Currently, you can't disable automatic backups, change the time they are activated, or storage duration.

Backup creation

Backups can be automatic or manual. Each type utilizes an incremental schema. When creating another backup, the DoubleCloud service checks the data parts for uniqueness. If identical data parts are in one of the existing backups and they are no older than 30 days, they are not duplicated. In this case, a backup references data parts from the previously created backups and the data is not uploaded to your storage again.

A random replica host is used to create a backup. If the host data is inconsistent, restoring clusters from backups does not guarantee complete data recovery. This issue may occur if the tables are not replicated on all shard hosts and are only hosted on some of these hosts.

Tip

DoubleCloud stores backup schema for all tables, but table data is backed up only for MergeTree family .

Backup storage

DoubleCloud stores all backups (automatic and manual) for seven days. Backup storage is not subject to quotas or limits for cluster storage space.

Backups are stored as binary files encrypted with GPG. Each cluster has its own encryption keys.

Backup integrity is checked on synthetic data using integration tests available in the service.

See also: