May 2012
Intermediate to advanced
528 pages
12h 24m
English
book
Information Storage and Management: Storing, Managing, and Protecting Digital Information in Classic, Virtualized, and Cloud Environments, Second Edition
by EMC Education Services
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Appendix D
Information Availability Exercises
Exercise 1
A system has three components and requires all three components to be operational 24 hours, Monday through Friday. Failure of component 1 occurs as follows:
- Monday = No failure.
- Tuesday = 5 a.m. to 7 a.m.
- Wednesday = No failure.
- Thursday = 4 p.m. to 8 p.m.
- Friday = 8 a.m. to 11 a.m.
Calculate the MTBF and MTTR of component 1.
Solution
The formula for MTBF is
Therefore,
The formula for MTTR is
Therefore,
So,
Exercise 2
A system has three components and requires all three components to be operational during 8 a.m. through 5 p.m. business hours, Monday through Friday. Failure of component 2 occurs as follows:
- Monday = 8 a.m. to 11 a.m.
- Tuesday = No failure.
- Wednesday = 4 p.m. to 7 p.m.
- Thursday = 5 p.m. to 8 p.m.
- Friday = 1 p.m. to 2 p.m.
Calculate the availability of component 2.
Solution
Operational hours are 8 a.m. through ...