IBM Support

Size of backup objects appears to be incorrect

Question & Answer


Why does the size of the object stored on the Tivoli Storage Manager server not reflect the actual size of the file that was backed up?


The Tivoli Storage Manager server database has 2 different size values for each object that is stored.


There are two primary size values stored on the Tivoli Storage Manager server for each object.

  • One is the size estimate for the object as received by the Tivoli Storage Manager server from the client.
  • The other is the actual amount of space the object ends up occupying on the server. This later value will include all header or frame data added to the object by Tivoli Storage Manager as well as the end effect that any compression may have had on the object versus the size the client sent.

The size estimate value can be found in the "show invo" (output from the Tivoli Storage Manager Server Inventory table) and the Object.Ids output.

The size as occupied space in server storage value can be found in the "show bfo" (BitFile Objects table) and the AF.Bitfiles (or DF.Bitfiles if on disk). This size can also be found in the query content output.

A Tivoli Storage Manager query by the client (regardless of whether the object is inactive) will show the size based on the information from invo. Thus, showing the size estimate for the object, not the actual size/space used on Tivoli Storage Manager (which is shown in the bfo output).

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Document Information

Modified date:
17 June 2018