Disaster recovery technology for Google Cloud Computing

Disaster recovery is an unpleasant topic, but it must be faced, take a company's email system as an example, some companies will back up the past emails, the frequency of backup may be daily or weekly, after the disaster occurs, the backup data will be restored to the system, although some can be restored, but this periodic backup only ensures the safety of the backed up data. The data that was last backed up to the time of the disaster was completely gone.