[oceanplexian]

I'm going to say that an hour a year is wildly optimistic. But even then, that puts you at 4 nines (99.99%) which is comparatively awful, consider that an old fashioned telephone using technology from the 1970s will achieve on average, 5 9's of reliability, or 5.26 minutes of downtime per year, and that most IT shops operating their own infrastructure contractually expect 5 9's from even fairly average datacenters and transit providers.

[nicoburns]

I was amused when I joined my current company to find that our contracts only stipulate one 9 of reliability (98%). So ~30 mins a day or ~14 hours a month is permissible.