This article lists the frequently asked questions related to a data backup or restore job.  

►Will my backups execute at the exact time specified on the Backup Definition?

The next scheduled backup job is checked once every 15 minutes to determine if the backup job should execute. If a previous backup is still running at this time, a new backup will not be started. The schedule is checked again in the next 15-minute interval to see if the previous backup is completed.

►How can I configure a partial backup for an org?

We offer the ability to exclude objects and fields from backups. For additional record level granularity, you can utilize Salesforce Roles or Sharing Rules of the Salesforce user account identified with your backup definition.

►Can we identify which records changed between the two dates?

Yes. The user can specify a Comparison Snapshot in the Snapshot Details window to compare all records which were modified between two dates. For more information, see Compare and Restore Records.