Increased storage space in the database and the resulting performance gains in the application programs are the most important benefits of data archiving. Therefore it is useful to know how much space the data to be archived takes up in the database.
Note that cluster tables are stored in a compressed form in the database.
It may also help to know in advance how much space the archive files that you create will need.
Data is compressed before it is written to the archive file.The extent of the compression depends on how much text (character fields) the object contains. Optimal compression can achieve a factor of five.
Estimates of the size of an individual data object are provided in the application-specific sections of this documentation. You can, however, also make a rough approximation (for example with your customer-specific archiving objects) of how much space the data to be archived occupies in the database and how much space the archive files will require.
For further details, see Calculating Storage Space Gained