The Mysterious Disappearing Tape Catalog

The documentation for Windows NT's backup utility (ntbackup.exe) claims that the utility builds a catalog of backed up files while it is backing them up. Microsoft tech support confirms this claim. However, my Exabyte EXB-8200 tape drive backups never found such a catalog. Every time I wanted to restore data from a tape (even if I wanted only one file), the backup software would insist on cataloging the tape. This process could take up to 2 hours—as long as the backup had taken. Eventually, I found that the backup software did in fact build a catalog in the C:temp directory, under a name such as 2c3f18b3.u01, but the backup software deletes this file when you exit. Now when I back up my systems, I copy this file to another directory before I close the backup software. Whenever I want to restore from that tape, I copy the file back into C:temp. If I am not sure which file I want, I copy the whole directory to C:temp. Then, I can see my list of tapes, complete with their catalogs (see Screen 1, page 182, for an example).

Note that this catalog is not the same thing as the backup log file, which is nothing more than a text file. The backup software generates the .u01 filenames automatically, and if you change them, the catalog will not show up in the Tapes window. Also, any backup added to a tape uses the same catalog filename as the first backup, so you have to come up with some scheme for handling the multiple instances of a file. I have not yet figured out a way to copy the catalog file to a different directory when I perform a scheduled, unattended backup (send me an email message if you have an answer). Why Microsoft engineers have not addressed this problem in the 6 years since NT's release is another mystery. Maybe they do not do backups.