I am storing my graphic work (which is mostly psd files) in a external usb drive.The folder is about 60 GB and obviously its pretty important cause its my life's work.Im keeping a copy of it in 2 other HDD's for safety. Because im working on the usb drive's folder my question is if there is any way that the changes that i make can be copied in the other 2 HDD's or even in one of them so i dont have to copy 60GB everytime that i m working/changing files on the original folder.