95% = 18.25 days of downtime per year<\/li>\n<\/ul>\nIf your target uptime allows for planned maintenance downtime, then that doesn’t count as unplanned downtime, as long as your system was only down for the length of time allowed. But don’t cheat yourself and retroactively classify unplanned downtime as planned, so it doesn’t affect your actual, measured uptime.<\/p>\n
For instance, if you have a 99.9% uptime goal for a 24×7 system, with a quarterly 4-hour maintenance window, then I would select 99.9% in the 24×7 target survey. For that same system, if the downtime was limited to the proscribed 4-hour window each quarter, and there was no other downtime *at all*, I would select 99.999% on the 24×7 measured uptime survey.<\/p>\n
Basic advice is to use common sense in how you answer. If you say you have a 24×7 system but you have a 12-hour maintenance window each week, I wouldn’t classify that as a 24×7 system.<\/p>\n
24×7 Systems<\/h1>\n
Survey 1: 24×7 system target uptime<\/strong><\/p>\n