In completion message and in the Status Reports, LiteSpeed indicates the amount of compression; how is this figure calculated?
The formula for caluclating the Compression % showed on the Status Report and in the completion messages:
Compression % = 100 - (Backup Size / DB Size)*100
Example: (Compression % of backup): 100-(0.4/2.10)*100 = 80.95 (the actual value is a little off since it's being rounded)
For a full back up, the DB size is the sum of the database size and the log files.