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<div class="moz-cite-prefix">On 2/2/2017 6:50 PM, Mark Smith wrote:<br>
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cite="mid:CAO42Z2xVDwQmd_9LRBgHL_93OHaBx5r5Zhe0-98+d1njTQMHWQ@mail.gmail.com"
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<div class="gmail_quote">On 2 Feb. 2017 4:30 pm, "Chad
Kelly" <<a moz-do-not-send="true"
href="mailto:chad@cpkws.com.au">chad@cpkws.com.au</a>>
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<div class="quoted-text">On 2/2/2017 3:19 PM, <a
moz-do-not-send="true"
href="mailto:ausnog-request@lists.ausnog.net"
target="_blank">ausnog-request@lists.ausnog.ne<wbr>t</a>
wrote:<br>
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Of course when people say we have 2 core data
centers, this should imply no<br>
data center is allowed to run over 50% capacity.
It's odd/strange that 3<br>
active core data centers should sound so unorthodox,
yet this is the only<br>
way to assure you can run your DCs at 65% and handle
a DC going black. Begs<br>
the question why 4 active core DCs isn't standard
architecture for core<br>
national infrastructure (which would assure high
availability under 75%<br>
load), and 2x efficient in idle infrastructure.<br>
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I like your idea in theory.<br>
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<div dir="auto">It's not theory. At one of the ISP's I've worked
for we scaled out BRASes this way. As you add units of
capacity, the required redundancy capacity required to cover a
single unit failure reduces across all the other units. It
works when you can divide your problem up into smaller
sub-problems and distribute them across a pool.</div>
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<div dir="auto">The argument sometimes used against it is that
it is more devices to manage. True, however that is tractable
by using config templates, automation and device management
platforms ("software defined networks"). The problems of
managing many devices is not a new one if you've spent any
time managing fleets of desktop PCs.</div>
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But building data centres costs money and a significant
amount of it.<br>
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<div dir="auto"><span style="font-family:sans-serif">You get
what you pay for. If you need high availability, you need to
be prepared to pay the price if it. If you can't afford the
price, then it is likely your availability requirements are
greater than they really need to be. Put a dollar cost
against the consequence of a failure, and you might find you
really do need to pay the price of the HA you want.</span><br>
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</span></div>
<div dir="auto"><span style="font-family:sans-serif">If you
can't afford to build DCs, you rent space in other people's
to meet your availability goals.</span></div>
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I remember when the Warrnambool exchange fire occurred,
a discussion was had around fire suppression and the
lack of it in a critical exchange for regional Victoria.<br>
<br>
Begs the question did they have appropriate levels of
fire suppression equipment installed?<br>
<br>
No good having multiple lots of equipment if its not
being protected from fire properly.<br>
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<div dir="auto">A better architecture is one where a facility
fire has a far smaller impact.</div>
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<div dir="auto">Your unit of expansion is your potential unit of
failure. Larger units of expansion, larger consequences of
failure.</div>
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<div dir="auto">Regards,</div>
<div dir="auto">Mark.</div>
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<blockquote class="quote" style="margin:0 0 0
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where you are coming from. <br>
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<p>A group of us were discussing the true meaning of cloud in terms
of web hosting the other day, I basically said that if the server
isn't setup with load balancing across multiple DC's that it isn't
really proper cloud hosting. It needs to be setup with high
availability. <br>
</p>
<p>A lot of providers use the term cloud when its not. <br>
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<pre class="moz-signature" cols="72">--
Chad Kelly
Manager
CPK Web Services
web <a class="moz-txt-link-abbreviated" href="http://www.cpkws.com.au">www.cpkws.com.au</a>
phone 03 9013 4853</pre>
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