I was trying to solve the following question in software architecture.
A software system crashed 20 times in an year and for each crash, it takes 2 minutes to restart. Calculate availability in that year
I used the formula MTBF/(MTBF+MTTR). How can I calculate MTBF and availability. Please help!
I did it like
MTBF = 365*24*60-40/ 20 MTTR = 2*20
MTBF in days is 365 / 20 (I don't think it makes any sense to take the 2 minutes recovery time into account here but your teacher might have a different opinion.)
Availability in minutes is: (minutes-per-year - 20 * 2) / minutes-per-year. It is common to write this value as a percentage, so you might multiply it with 100.
As a general advice, try to understand what these values mean, then the formulas will become evident.
