Backups in Managed Service for ClickHouse®
Managed Service for ClickHouse® provides automatic and manual backups. An automatic backup is created once a day at around 1 AM in the cluster timezone. Backups are stored in the same region as the cluster and retained for seven days.
Backup restrictions
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You can create backups only for selected ClickHouse® shards.
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You can’t turn off automatic backups, adjust their activation time, or change the retention period.
Backup creation
Both automatic and manual ClickHouse® backups on DoubleCloud use an incremental schema. When creating a new backup, data parts are checked for uniqueness. If identical data parts are already present in an existing backup and they’re less than 30 days old, they aren’t duplicated. For such data parts, a new backup refers to the corresponding data parts from previous backups and these parts aren’t uploaded to your storage again.
Backups are created from a random replica host. If the host data is inconsistent, restoring the cluster from a backup doesn’t guarantee complete data recovery. This may happen if tables aren’t replicated across all hosts.
Note
DoubleCloud stores backup schemas for all tables, but table data is backed up only for MergeTree family tables.
Backup storage
DoubleCloud retains automatic and manual backups for seven days. Backup storage isn’t 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.