The data is currently stored in a 9TB RAID array, with many users having many files and directories. We'd like to back it up to five 2TB external hard drives, but since we only have one free USB port, this must be done sequentially. This means that once hard drive #2 is plugged in, #1 is unplugged, and we won't know what was originally on hard drive #1 unless the software remembers it.
One solution would be to assign every file or directory to a hard drive beforehand, and then follow through with this as they are connected. Is there a straightforward way to do this?