Thus spake "Richard A Steenbergen" <ras@e-gerbil.net>
Throw in some assumptions (which may or may not be true, I'll agree that some of their numbers are a little "off") that every one of those failures involves some service impact, you could easily make a case that one box which doesn't go down is better than two boxes which routinely go down.
If a tree falls down in a forest, but service isn't affected, do we care if the tree falling made a noise? If you have two devices which are up 99% of the time, then one of the two is up 99.99% of the time. While designing with two of everything is indeed more complex, it's often simpler than designing a single product that's more reliable. Having two of everything also simplifies maintenance, since you don't care (much) about an individual box being down. Public ATM networks are hell to maintain because every node must be up 24x7 and simple things (to routerheads) like a software upgrade are a 3+ month project because it must be done online without dropping a single cell. S Stephen Sprunk "God does not play dice." --Albert Einstein CCIE #3723 "God is an inveterate gambler, and He throws the K5SSS dice at every possible opportunity." --Stephen Hawking