copy them to a USB stick, label it, and keep it someplace safe. You can copy
the important files to a CD-RW disc (up to 700MB in size), or a DVD-RW
disc (up to 8GB for data) if you still have that hardware. Most users have
switched to using an external hard drive for backups because they are
becoming less and less expensive and hold a great amount of data, or they
have moved backups online.
In addition to configuration and data files, you should archive each user’s
/home directory and entire /etc directory. Between the two, that backup
would contain most of the important files for a small system. Then, if
necessary, you can easily restore this data from the backup media device you
have chosen after a complete reinstall of Ubuntu.
Experts used to say that if you have more data than can fit on a floppy disk,
you really need a formal backup strategy. Because a floppy disk only held a
little over 1MB (and is now incredibly obsolete), perhaps we should change
that to “if you have more data than can fit on a cheap USB stick.” In any case,
some formal backup strategies are discussed in the following sections. We use
a tape media backup as an example for convenience because they have been
incredibly popular and standard in the past and are still quite common, even
as people move to new options such as portable hard drives and cloud storage.
Full Backup on a Periodic Basis
A full backup on a periodic basis is a strategy that involves a backup of the
complete file system on a weekly, bi-weekly, or other periodic basis. The
frequency of the backup depends on the amount of data being backed up, the
frequency of changes to the data, and the cost of losing those changes.
This backup strategy is not complicated to perform, and it can be
accomplished with the swappable disk drives discussed later in the chapter. If
you are connected to a network, it is possible to mirror the data on another
machine (preferably offsite); the rsync tool is particularly well suited to this
task. Recognize that this does not address the need for archives of the recent
state of files; it only presents a snapshot of the system at the time the update is
done.
Full Backups with Incremental Backups
Another scheme involves performing a full backup of the entire system once a
week, along with a daily incremental backup of only those files that have
changed in the previous day, and it begins to resemble what a system
administrator of a medium to large system traditionally uses.