Recovery

One of the major goals of Bacula is to ensure that you can restore tapes (the word tape is also used to include disk Volumes) that you wrote years ago. This means that each new version of Bacula should be able to read old format tapes. The first problem you will have is to ensure that the hardware is still working some years down the road, and the second problem will be to ensure that the media will still be good, then your OS must be able to interface to the device, and finally Bacula must be able to recognize old formats. All the problems except the last are ones that we cannot solve, but by careful planning you can.

Since the very beginning of Bacula until today, there have been two major Bacula tape formats.

Though the tape format is fixed, the kinds of data that we can put on the tapes are extensible, and that is how we added new features such as Win32 data, encrypted data, etc. Obviously, an older version of Bacula would not know how to read these newer data streams, but each newer version of Bacula should know how to read all the older streams.

If you want to be 100% sure that you can read old tapes, you should:

Try reading old tapes from time to time – e.g. at least once a year.
Keep statically linked copies of every version of Bacula that you use in production then if for some reason, we botch up old tape compatibility, you can always pull out an old copy of Bacula.