[Beowulf] RE: Capitalization Rates - How often should you replace a cluster? (resent - 1st sending wasn't posted ).

[Jon Aquilina]

so basically all those old machines end up on ebay

On Tue, Jan 20, 2009 at 8:35 AM, Greg Lindahl <lindahl at pbm.com> wrote:

> On Tue, Jan 20, 2009 at 08:14:35AM +0100, Jon Aquilina wrote:
>
> > in all honesty is there a need really to replace the cluster. why not
> just
> > add onto it?
>
> Think about it: if you pay 1/3 the cost of a new node per year in rent
> and utilities, and nodes get twice as fast for the same cost every 18
> months. Let's say that means each year performance increases by 60%
> (close enough for our purposes.)
>
> Year 1: I pay 1.33$ for 1 unit of performance
> Year 2: I pay 0.33$ for 1 unit of performance -- or 1.33$ for 1.6 units of
> performance
> Year 3: I pay 0.33$ for 1 unit of performance -- or 1.33$ for 2.56 units of
> performance
> Year 4: I pay 0.33$ for 1 unit of performance -- or 1.33$ for 4.1 units of
> performance
>
> Hey! In year 4 it's about the same to keep the old cluster, or throw
> it out and buy a new one. (If I want to spend the same $$, I can buy a
> cluster 1/4 the size, but same performance, as the original one.)
>
> And in year 5, it's a big win to buy the new stuff.
>
> If you don't pay rent and utilities, then sure, you'll probably keep
> as much junk as will fit in whatever space you have. Maybe the cluster
> I put together in 1998 at UVa is still running...
>
> -- greg
>
>
>
>


-- 
Jonathan Aquilina
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