I'm currently running Windows 7 x64 with a secondary data drive encrypted with Truecrypt. For the past 6 months or so I have been backing up the files on this drive manually to two other drives; using the 'overwrite older only' option in Teracopy for every conflict (as Teracopy won't let me set that option globally I have to do it manually for each conflict!), then a file analyser to manually find the files that have since been deleted on the source to delete them on the target.
I had a scare yesterday where the internal disk started clicking and then disappeared from Windows entirely. Fearing a failure I extracted the drive from my machine and placed it in my external USB caddy and it thankfully came up on my Arch laptop, then my Windows machine. In my panic I bit the bullet and installed SyncToy to automate this so I could sleep while it ran overnight. I used the 'echo' option and enabled the 'check file contents' for the first run to ensure it did it's job properly.
After completion, it appears that the new files have been moved across but the old files that existed on the target have not been deleted. I'm basically back in the same situation as Teracopy without a large amount of clicking, but still facing the prospect of manually analysing the drives with a duplicate finder.
As I use 2 externals in rotation as the target, is there some sync program for Windows that will smart-delete files on the target that don't exist on the source, while leaving existing unchanged files and adding new ones - with as little user input as possible? (I quite like this 'sleeping-while-it-works' idea)