chkdsk d: /f
xcopy c:\path d:\path /vs
Robocopy also has options for file verification.
One of the problems with off-site storage is that it can get wiped out, too. Keeping things is waterproof cases with some desicant is a good idea. There aren't any cases which will protect film against fire, though. All of the fireproof safes protect paper against fire, but film has a lower temperature where it can be ruined.