When 100% is not 100%, this is related to one of the things I mentioned in my presentation yesterday at Future of Web Apps. You would think for how much they’re charging Rackspace could afford a less draconian interpretation of their “100%” promise, either that or they should invest more into their infrastructure.
Five-nines reliability (99.999%) is the maximum practicable uptime.
99.999% = 26 seconds in a month.
That’s shorter than a reboot.
A couple of minutes even is a lot different than 20 minutes. 100% should be closer to 100% than 20 minutes. And there there is also how many times a day, month, year it happens.
As Barry writes in his own post’s comments “Yes, everyone knows that 100% uptime is not possible, but a 100% uptime SLA is not all that unreasonable. The idea behind it is that that the figure “100%” in your marketing material will generate enough revenue to more than offset the SLA credits that will be given out when there is an outage. I am just surprised that they didn’t stand behind the SLA or that they interpreted it this way.”