I had a serious fault two years ago, when several forest fires knocked out electric power for the two lines feeding the datacenter. Electricity failed three or

I had a serious fault two years ago, when several forest fires knocked out electric power for the two lines feeding the datacenter. Electricity failed three or four times in short periods, and for some reason this wrecked havoc on the UPS-generator combo, and power went out. We were down for six hours and mad at the co-location company. Other than that, thirty minutes downtime 14 months ago when the public-facing redundant routers mis-detected a failover, failed STONITH and entered split-brain status. I wouldn't commit to better than 99.9% with our infrastructure (single datacenter with remote data backups) but we exceed the metric most years (99.99% in all but one of the last ten years).