1. A method comprising: initiating a backup operation of data including a plurality of items; interrupting the backup operation, where interrupting occurs after a portion of backup data generated by the backup operation has been completed; receiving an input to resume the backup operation; identifying the completed portion of the backup data, including comparing timestamps on written backup data to a timestamp of a last completed backup operation; and performing a backup of a remaining uncompleted portion of the data using one or more processors.