windows 2012 - dedup
If you have some archive data that you would like to copy onto a win 2012 server, but dont know how to estimate the end volume size (if VM etc). Start small - about 1/2 of the total capacity of the drive. Robocopy the data onto the drive until nearly full, manually run dedupe, wait until complete, continue robocopy, repeat and rinse. There will be occasions where you will run out of disk space at that point its time to extend your disk.