When a tablet starts, Vitess checks the value of the -restore_from_backup command-line flag to determine whether to restore a backup to that tablet.
- If the flag is present, Vitess tries to restore the most recent backup from the Backup Storage system when starting the tablet.
- If the flag is absent, Vitess does not try to restore a backup to the tablet. This is the equivalent of starting a new tablet in a new shard.
For more information on restoring and managing backups please follow the link here.