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linuxgziparchivetar

Tar archive: How reliable is append?

I noticed that the -a option in TAR allows appending files to an existing archive. How reliable is this for creating incremented backups of a set folder? Is there anyone here who can share their experiences?

From the TAR manual:

 -A, --catenate, --concatenate
       append tar files to an archive
Solution

  • Since tar is a Tape Archive the last file will physically be appended to the archive, with an header. There is no index table which could cause issues.

    Thus it's very reliable. Even if the process gets interrupted halfway you can seek the archive until the last complete entry and delete everything after it and everything will be as if you never tried to append to the archive.