表A-1：可用性时间表

    可用性级别 允许的不可用窗口时间

    		每年 每季度 每月 每周 每天 每小时
    90% 36.5 days 9 days 3 days 16.8 hours 2.4 hours 6 minutes
    95% 18.25 days 4.5 days 1.5 days 8.4 hours 1.2 hours 3 minutes
    99% 3.65 days 21.6 hours 7.2 hours 1.68 hours 14.4 minutes 36 seconds
    99.5% 1.83 days 10.8 hours 3.6 hours 50.4 minutes 7.20 minutes 18 seconds
    99.9% 8.76 hours 2.16 hours 43.2 minutes 10.1 minutes 1.44 minutes 3.6 seconds
    99.95% 4.38 hours 1.08 hours 21.6 minutes 5.04 minutes 43.2 seconds 1.8 seconds
    99.99% 52.6 minutes 12.96 minutes 4.32 minutes 60.5 seconds 8.64 seconds 0.36 seconds
    99.999% 5.26 minutes 1.3 minutes 25.9 seconds 6.05 seconds 0.87 seconds 0.04 seconds