Backups in ClickHouse®
The ClickHouse® provides automatic and manual backups. A backup is automatically created once every day, around 1 a.m. in your specific timezone.
Backups have the following temporary restrictions:
At the moment, you can create backups only for specific ClickHouse® shards. The capability that allows creating backups for clusters is currently under development.
ACurrently, it's not possible to turn off automatic backups, adjust their activation time, or change the duration of storage.
Backups can be automatic or manual. Both types utilize an incremental schema. When creating another backup, the Managed Service for ClickHouse® checks the data parts for uniqueness. If identical data parts are in one of the existing backups and they're no older than 30 days, they're 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 doesn't guarantee complete data recovery. This issue may occur if the tables aren't replicated on all shard hosts and are only hosted on some of these hosts.
DoubleCloud stores backup schema for all tables, but table data is backed up only for MergeTree family
DoubleCloud stores all backups (automatic and manual) for
7 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.