Mandatory and Full Consistency Checks
By creating backups, a user is sure that the backed up data is possible to restore if required. Unfortunately, this may be not 100% true if backup data on backup storage is corrupted for some reason. The occurrence of data corruption can have many reasons, ranging from technical problems with the cloud provider’s service to industrial sabotage.
The consistency check is a mechanism that prevents possible data losses. By finding any discrepancies, a user is notified if some objects are missing in backup storage or there is a mismatch between object sizes or modification dates.
Once a consistency check is started, an object list is requested along with metadata from backup storage.
In all cases, the user is notified about backup data damage. If some discrepancies are detected, Backup for Windows executes full backup automatically. Possible damage in previous backup generations is also monitored.
Thus, with the consistency check completed, you are aware of any possible mismatches and are able to plan further actions to solve possible issues.
Mandatory Consistency Check
The mandatory consistency check is a current-generation check. The current generation consistency check is mandatory for all plans and is executed at the start of a backup plan in the current backup format.
Full Consistency Check
Full consistency check implements all backup plan generation checks except the current generation. If a full consistency check is successfully completed, a user can be sure that backed up data is guaranteed to be restored.
You can enable full consistency check in the backup plan settings on the Backup Consistency Check step.