Single Instance Storage Reports display incorrectly

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Single Instance Storage (SIS) Reduction by File Type, Single Instance Storage Reduction per Vault Store Group, Single Instance Storage Reduction Summary Operation Reports display incorrect information than what is described in the documentation.


In the Administrator and Reporting Guide it shows inaccurate information for SIS reports column "Total On-Disk Size", "Total Original Size" and "Total Compressed Size". This technote is to inform of the correct definition of the current SIS reports columns with examples.


-Total On-Disk Size is the sum of the sizes of all items that have been archived without being SIS.
-Total Original Size is the sum of the size of the items that have been SISed before they were archived.
-Total Compressed Size is the sum of the sizes of the SIS Parts. This includes all SIS Part File (.DVSSP) and Large File SIS Part File (.DVFSP) but excluding Saveset file (.DVS).

Total On-Disk Size

Total On-Disk Size is the sum of the ItemSize in the SaveSet table or the sum of the ArchivedItemsSize in the Archivepoint table, divided by 1024 twice (to turn into a GB figure)


If the sum of the ArchivedItemsSize is 2048, then the figure on the report would be: 2048/1024/1024, 0.00195 (rounded as 0.002)


Sending a message with a 5 MB attachment, Outlooks says that this message is: 5,193,843 bytes and the ItemSize in the SaveSet table once it has been archived is 2048 KB.  On disk, ie on the file system, the DVS file is 9436 bytes, and the DVSSP file is 2,087,063 bytes.

The report shows:


If I now send in another message, with the same 5 MB attachment, only a new DVS file (9271 bytes) is created, no new DVSSP file is generated.  In the SaveSet table a new row is created with the ItemSize saying 2048 Kb.

This is the report afterwards:


So I've stored 2 items of 2048 Kb each, giving me 4 Mb in the report.   Remember that's the figure without any SIS.  And remember it doesn't tie back to the size of the files on disk right now, just what they would have been if there was no SIS.

Total Original Size


If you were to send 1000 5Kb message the report would show:


Total Original Size = 0, since 5 Kb messages are below the SIS threshold, and don't fall out to being a DVS file and a DVSSP; they are just a DVS file.  

Afterwards if you were to send a message with a 5 Mb attachment the report would show:-


Note: Total Original Size is 5 Mb now, since we have 1 SISPart and the original size of it was 5 Mb.  The Total Compressed Size column now also has a figure in it; it shows the size of the SISPart(s).  

If another message was sent with the same 5 Mb attach you would see:


Note: At this time the sum of the ArchivedItemsSize is 13094, so the Total On-Disk Size on the report would be: 13094/1024/1024, rounded, as 0.012.

Note: At this time the Total Original Size is 10 Mb, since we have two 5 Mb attachments (the same attachment each time).  You can also see the other figures in the report reflect this.

Total Compressed Size

Total Compressed Size is the sum of the sizes of the SIS Parts.  This includes all DVSSP and DVFSP.

If you were to send a message with no body and a 5 Mb attachment you would see the following in the report:


If you then sent a message with 88.9 Mb text file attachment you would see:-



Veritas Corporation has acknowledged that the above-mentioned issue is present in the version(s) of the product(s) referenced in this article.

There are currently no plans to address this issue by way of a cumulative hotfix or service pack in the current or previous versions of the software at the present time. This issue may be resolved in a future major revision of the software at a later time, but is not scheduled for any release. If you feel this issue has a direct business impact for you and your continued use of the product, please contact your Veritas Sales representative or the Veritas Sales group to discuss these concerns. For information on how to contact Veritas Sales, please see

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