Native utilities are the backup utilities that you find in a standard Unix distribution. I’ll admit that these utilities are rather boring. They do nothing fancy and they have many limitations, some of which have been there since they were originally written to back up a PDP-11 to a 9-track tape. (In sixth and seventh edition Unix, it was still called restor —a throwback to the Multics days.) Some of these utilities have bugs that persist to this very day. (They’ve finally fixed the “tape-rewinding” bug in dump, but only on some Unix versions.)
Yet these native backup utilities do have a few features that have not been duplicated by commercial backup vendors. These features will always be there, and they don’t cost extra. They also work basically the same everywhere, with only a few minor differences. Whether you’re just starting out in the backup world or you’re an experienced systems administrator, you need to be familiar with these utilities.
This chapter describes the benefits and pitfalls of several utilities. dump and restore are usually the best option if they are available. After dump and restore, cpio has the best functionality, but it is slightly less user friendly than its cousin tar. tar is incredibly easy to use and is much more portable than either dump or cpio. If you have to back up raw devices or perform remote backups with tar or cpio, dd will be your new best friend.
This chapter begins with an overview ...