I don't use index files at all. In case of disaster, I expect to have to get a new machine and tape drive, with tons of disk, and put each tape in, reading it from start to finish (streaming) and just write each file to disk. Then, I'll be looking for the most recent 0 of each fs, and the most recent 1, etc., and doing full restores.
Or are you concerned about the ability to do restores with indices on regular machines after your tape server explodes? You could perhaps rsync the index files to someplace offsite, too. -- Greg Troxel <[EMAIL PROTECTED]>