On the report the total % of disk space is 86% which includes all unused space. Where is the other 14% which totals over 400Gb on our system ? IBM replied that it's because the data is in use at the time and the data gathering should be run in a dedicated system. I find it hard to believe that 400Gb is in use (each week) when the job is run at a quiet period. Since the job has to run in batch it's difficult to run dedicated especially on a production machine. Is there another way of finding out where this 'missing' 400Gb is ?