I have a collection of rather large files/directories (ranging anywhere from 40GB-200GB per file) that I need to span across a set of disks (or tapes) of fixed size (in this case 800GB). The trick is, I want to span these efficiently so the least amount of space is available on each disk/tape (thus minimizing wasted space). I'm looking for some sort of tool/calculator/script where I can input the file sizes (or preferably it can scan a directory) and it can output the most effective way to span them (tape1: files B+U+Z+Q, tape2: files A+F+L+Z, tape3: files P+G+M, etc) Does such a thing exist? Thank you in advance.

If you use winrar you can split files into as many and as small/large files you want. From there you could write a script that moves the files into different folders, and after that it's just a matter of backing the folders up to different tapes. I'm not entirely sure, but I think you can script winrar commands as well, google it to find out more. If you can script winrar as well you could make the whole process automatic.

chaynik not sure what your thinking is regarding your question. You would not want to "span" a file over multiple single disks. You are asking for file corruption/complete loss of data if one of those disks died. What you would want to do is raid the disks, choose the default cluster size of 4kb and let the system handle the file optimization. You also need to understand the difference between tape and drive. Tape in linear, drive is not. Backup can split a backup over multiple tapes. This has its risks just like spanning over multiple standalone disks. If you backup a file using three tapes and any one tape is defective you lost it all. Just keep these caveats in mind as you move forward.