The myth of 99.99% uptime

Most of the hosting providers promise you an uptime of 99.99% and that very appealing to anyone.potential1[1]

But did you bothered to do the math ?

365 days in one year x 24 hours a day x 60 minutes a day = 525600 minutes in one year

From 525600 we have to extract 0.01% the downtime of that network and see how much is it.

So (525600 minutes in one year x 0.01 down time) / 100 = 52.56 minutes#

Until now the math checks out so in conclusion the down time of a network will be 52.56 minutes, a network that promises you 99.99% uptime

Well it seems like that number is still too big but from the perspective of a network administrator that number is very very very small.

Why ? It’s very simple.

Network components break down.

Cables, switches, routers, servers, server components, UPS and so on (the list is too big to write it now)

Any component requires time to be replaced on any segment of the network.

Lets take example the simplest UTP cable or the patch as everyone calls it.

A patch is a UTP cable used to connect network components common use connects a server to a switch or a router.

Looks like a simple component but a very important one piece.

If that cable fails the connection between the server and switch/router breaks and as a result the server will be offline from the network.

Solution is very simple, replace the cable, but for that you will need someone to do it. In ideal conditions the techy will do this in no more the 5 minutes, time needed to identify the problem, get the new cable, go to the fault, take out the faulty cable and replace it with the new one.

In not so ideal conditions the techy is out to lunch, or he doesn’t have a patch made, or he misplaced the key to the spare parts cabinet or any other unforeseen event will increase the time until fixing the problem up to 10 – 20 minutes and that if you are in business hours.

Imagine what will happen if a fault will occur outside business hours or in the middle of the night, how fast do you think that the fault will be fixed ?

Given this scenarios in ideal condition on a simple fault it takes 5 minutes to resolve it so that gives as 10 faults a year to stay in the 0.01% down time.

In the “not so” ideal conditions in business hours we have an average of 15 minutes to fix the fault so that gives as not more the 3.4 faults to stay in the 0.01% down time.

If we are out of business hours I imagine that at some point it can take even 1 hour to fix a problem (the techy is home, or is sleeping and he doesn’t hear the alarm), so basically in this case we are already over the 0.01% down time just for one fault.

Now… after reading this, what do you think? is there such a thing as 99.99% uptime ?