Determining the size of a DB2 backup object

Answer

When the IBM Spectrum Protect Backup/Archive client displays the size of an object, it is using the explicit value that is stored with the meta data regarding this backup. In the case of a DB2 backup, the stored meta information does not contain an accurate size as it is using the estimate, not the actual size of the data.

There are two primary size values stored on the server for each object. One is the size estimate for the object as received from the client. The other is the actual amount of space the object occupies on the server. This later value will include all header or frame data added to the object by the IBM Spectrum Protect Server as well as the end effect that any compression/deduplication/etc may have had on the object versus the size the client sent.

• The size estimate value can be found in the show invo and the Object.Ids output.
• The size as occupied space in server storage value can be found in the show bfo and the AF.Bitfiles (or DF.Bitfiles if on disk). This size can also be found in the query content or select output against the contents table (although the query content output is rounded for larger objects)

select * from backups where nodename='NODENAME'

show bfo <object_id>