I previously asked how to create an index of a multi-volume archive. That question contained the assumption that using
tar --list after writing my volumes would have to re-read all my data and hence be slow
However, is that true? Will it have to re-read every byte, or is GNU tar intelligent enough to seek over archive members and hence list the archive contents very quickly?
I did a bit of testing with a 35GB tar file and the result (completion within 2 seconds) seems to indicate that
--list is indeed fast, though I don't completely trust my testing methodology and couldn't rule out the influence of caching or something else I don't understand.