Critique?

[dsr at tao.merseine.nu (Dan Ritter)]

On Thu, Mar 01, 2007 at 01:07:04PM -0500, markw at mohawksoft.com wrote:
> >
> > These calculations will tell you how much it's worth spending on increased
> > uptime. Some businesses need it, some won't. Some commitments to 24x7
> > service will make others cheaper, since you may have already sunk the
> > cost of building out a second datacenter, or a 24x7 operations crew.
> 
> You are missing the point, and this is sort of the point I tried to make.
> You can't rely on a 99.999% uptime from a data center.

Right. You need more than one, and a method of switching or
balancing between them seamlessly.


Can you reconcile this:

> It is sort of like the joke, buying a lottery ticket only slightly
> increases your chance of winning. My systems have had uptimes that exceed
> years, and they aren't even anything special.

with this:

> I would like to know if any site anywhere has ever achieved 99.999% uptime
> over the course of one or two years. If no site has, then there is no
> basis for any such estimate.

?

I would also suggest that there are several customers of Akamai
who have managed "99.999% uptime over the course of one or two
years", if you define uptime as the ratio of "customers could have accessed
those services" vs "no customer could access those services".
Probably many others.

-dsr-

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