section 2 - availability

3 nines

99.9% uptime

8,760 hours are avaiable and can only be down for a maximum of 8.76 hours

5 nines

99.999%

system guarantees a downtime of no more than 5.26 minutes in a year

gold standard

99% uptime

3.5 days of downtime per year

availability helps

ensure business continuity, maintaining customer trust, upholding an organization’s reputation

best strategy to maintain high levels of availability

redundancy

redundancy

duplication of critical components or functions of a system with the intention of enhancing its reliability

types of redundancy

server redundancy, data redundancy, network redundancy, power redundancy

server redundancy

involves using multiple servers in a load balance so that if one is overloaded or fails, the other servers can take over the load to continue supporting end users

data redundancy

involves storing data in multiple places

network redundancy

ensures that if one network path fails the data cna travel through another route

power redundancy

involves using backup power sources to ensure that an organization’s sysmems remain operational during periods of power disruption or outages within a local service area