discusses some technologies that are a bit outdated for the enterprise but
might be useful to a hobbyist with cheap and easy access to older equipment.
If you want to use an online cloud service, take what you learn here, read
everything made available by your cloud service provider, and then do your
homework to design a suitable backup solution for your unique needs. This
could be as simple as putting all your important files in a Dropbox-style cloud
folder that automatically updates to another computer you own. This can
work well if you are a casual consumer-grade user backing up simple
documents and a few legally owned media files and remember that services
like these generally do not guarantee that your data will be permanently
backed up (especially with the free versions). Although we’ve not had
problems with these solutions, we warn that they are not enterprise backup
solutions. You might need to study up on Amazon Web Services, OpenStack,
or other cloud providers and learn the fine details of their services to see if
they suit your needs.
NOTE
If you are a new system administrator, you might inherit an existing backup
strategy. Take some time to examine it and see if it meets the current needs
of the organization. Think about what backup protection your organization
really needs and determine if the current strategy meets that need. If it does
not, change the strategy. Consider whether the current policy is being
practiced by the users, and, if not, why it is not.
BACKUP LEVELS
UNIX uses the concept of backup levels as a shorthand way of referring to
how much data is backed up in relation to a previous backup. It works this
way: A level 0 backup is a full backup. The next backup level is 1.
Backups at the other numbered levels will backup everything that has
changed since the last backup at that level or a numerically higher level.
(The dump command, for example, offers 10 different backup levels.) For
example, a level 3 followed by a level 4 backup generates an incremental
backup from the full backup, and a level 4 followed by a level 3 generates a
differential backup between the two.The following sections examine a few of the many strategies in use today.
Many strategies are based on these sample schemes; one of them can serve as
a foundation for the strategy you construct for your own system.
Simple Strategy
If you need to backup just a few configuration files and some small data files,