Increasing availability

There are two ways to increase the availability:

If we took the three nines example above and made the MTTR only six minutes (0.1 hours for easy calculations) our availability would now be:

1000 / (1000 + 0.1) Figure 1. MTBF of 1000 hours, MTTR of six minutes.

which is 0.9999, or four nines — ten times better!