In a backup world,
Recovery Point Objective (RPO) defines points you can recover to. For example,
doing hourly backups will ensure that you can always recover to a state that is
no later than an hour before a disaster. This is usually referred to as “one
hour RPO.” But
this is not enough. What if you need a file that was deleted a month ago? One-hour-old
backup will not help: You need at least
a month-old backup, or a year-old backup.
Rule #1: RPO should not only define the
latest point you can recover to, but also a set of older points to
which recovery is possible.
At the same time, keeping
all backups forever is usually not a feasible option. With hourly backups, you
would end up having about 8,760 recovery points every year, which becomes
unmanageable very soon. It is not possible to keep all the recovery points and some
will need to be deleted. However, simply