Seems like a case of over-optimism. :-) LTO4 physical capacity is a maximum of 800 GB. You may not get that or much more depending upon data compressibility, physical file sizes, and tape block sizes. You could reduce your Estimated Capacity value if the 1.0 T results in annoying reporting. The mailing list archives hold past discussions on many topics, where http://adsm.org/forum/showthread.php?16498-ESTIMATED-CAPACITY-OF-LTO4-s is like this one.
Richard Sims
