@carolynb -- there are over 720 hours per month (24 hours/day times 30 days/month).
So, an outage of up to 7.2 hours is just a 1% "down-time" (99% "up-time").
Not perfect, but pretty good. Having 99.9% up-time per month would be 0.72 hours (43 minutes). A worthy goal.
Outages can be caused by:
- back-hoes cutting a fiber-optic cable,
- flooding when torrential rains exceed the storm-drain system,
- fire (there was one in downtown Vancouver, a few years go, in a server-room)
- others (see: "StrikeForce" screw-up)
The entire world is now completely dependent on technology for online banking and credit-card transactions.