Business continuance and disaster recovery corporate objectives should be based on the following criteria:

Availability is defined with five classes as:

mission critical where the server or data must be available 99.999% of the time - the "five-nines" level of protection equates to 5 minutes downtime per year

business vital is 99.99% availability = 53 minutes downtime per year

mission important is 99.9% or 9 hours per year

data important is 99% or 3.6 days per year

data not important is 90% or 36 days per year



Recovery Time Objective (RTO) is defined as the maximum time allowable for recovering data:

mission critical data the RTO (taken as .00001 of the total year) is 1.5 minutes

business vital data the RTO is 15 minutes

mission important data the RTO is two hours

data important for productivity the RTO is one day

data not important to operation the RTO is one week



Recovery Point Objective (RPO) is how much work in progress that can be lost:

Tier 0 - No off-site data

Tier 1 - Data backup with no Hot Site

Tier 2 - Data backup with a Hot Site

Tier 3 - Electronic vaulting

Tier 4 - Point-in-time copies

Tier 5 - Transaction integrity

Tier 6 - Zero or little data loss

Tier 7 - Highly automated, business-integrated solution