Differences between version 3 and previous revision of Availability.
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| Newer page: | version 3 | Last edited on Tuesday, November 19, 2002 3:49:05 pm | by PerryLorier | Revert |
| Older page: | version 2 | Last edited on Tuesday, November 19, 2002 3:44:25 pm | by PerryLorier | Revert |
@@ -2,4 +2,14 @@
Not to be confused with [Reliability] which doesn't include scheduled downtime. For example "Sunlight" is very Reliable (it comes up every day!) but is only about 50% Available (it's dark lots too, but people expect that).
Note, rebooting your machine once a week to get rid of any "issues" that might have cropped up, means your system is very Reliable (assuming no issues actually occur) but not that Available.
+
+|||^__Availability__
+|__Percentage__|__"Nines"__|__Time__
+| 9% | 1 | Up one month a year
+| 99% | 2 | Down about one month a year
+| 99.9% | 3 | Down 3 days a year
+| 99.99% | 4 | 8 hours a year
+| 99.999% | 5 | just under 1 hour a year
+| 99.9999% | 6 | 5 minutes a year
+| 99.99999% | 7 | 30 seconds a year
