Data Protection Advisor - Slight differences between ‘Size Scanned’ in Backup Job Details datasource and ‘totalsize’ in mminfo output
Summary: The Size Scanned field in backup reports can be lower than the totalsize returned by mminfo; due to storing Size Scanned in megabytes and rounding, with offset column holding byte difference. ...
This article applies to
This article does not apply to
This article is not tied to any specific product.
Not all product versions are identified in this article.
Symptoms
Slight differences noticed between the Size Scanned field in the All Jobs report and the Totalsize in mminfo output.
For example:
Totalsize (NW): 779,329,431,284 B
Size Scanned (DPA): 779,328,946,176 B
We are reporting 485,108 B (473.7 KB) less
Cause
This is not DPA issue but design behavior
The reason for storing backup job sizes in the DPA database in MB is to cater for large numbers. But because of that, sometimes the values are rounded to the nearest MB. The difference between the actual value and the rounded value is stored under the offset column.
In above example after enabling the 'Size Scanned Byte Offset (KB) confirmed the offset value was 473.738KB which perfectly aligns the encountered difference.
Further research on DPA technical documentation online https://support.emc.com/docu69721_Data_Protection_Advisor_6.2_SP3_Report_Ref_Guide_.pdf?language=en_US page 183:
Size Offset and Size Scanned Offset values are gathered by the backup modules, but by default are not displayed in the reports. Size Offset is the number of bytes that should be added to or subtracted from the Size field to return the job size in bytes. Size Scanned Offset is the number of bytes that should be added to or subtracted from the Size Scanned field to return the job size in byte
The reason for storing backup job sizes in the DPA database in MB is to cater for large numbers. But because of that, sometimes the values are rounded to the nearest MB. The difference between the actual value and the rounded value is stored under the offset column.
In above example after enabling the 'Size Scanned Byte Offset (KB) confirmed the offset value was 473.738KB which perfectly aligns the encountered difference.
Further research on DPA technical documentation online https://support.emc.com/docu69721_Data_Protection_Advisor_6.2_SP3_Report_Ref_Guide_.pdf?language=en_US page 183:
Size Offset and Size Scanned Offset values are gathered by the backup modules, but by default are not displayed in the reports. Size Offset is the number of bytes that should be added to or subtracted from the Size field to return the job size in bytes. Size Scanned Offset is the number of bytes that should be added to or subtracted from the Size Scanned field to return the job size in byte
Resolution
Create a custom report based on the All Jobs system template report to show the values in B. To make it accounts for the offset add the Size Scanned Offset column to the Size Scanned column to match the TotalSize B value reported by NW mminfo.
Contact Dell EMC technical support for more details
Contact Dell EMC technical support for more details
Affected Products
Data Protection AdvisorArticle Properties
Article Number: 000064071
Article Type: Solution
Last Modified: 09 Dec 2025
Version: 4
Find answers to your questions from other Dell users
Support Services
Check if your device is covered by Support Services.