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You were pre-conditioned to believe that it's a feature. Traditionally, datacenter itself is supposed to provide HA for both the power and the network. "Availa

You were pre-conditioned to believe that it's a feature. Traditionally, datacenter itself is supposed to provide HA for both the power and the network. "Availability zones" exist for AWS convenience, not for yours. It allows for cheaper and simpler DC ops, removes the need for redundant generators, simplifies network design, and makes "under-cloud" maintenance easier. It's a feature for them, a headache for you, and a (brilliantly addressed) challenge for AWS product marketing.

closeparen 6y ago
I don’t know about you, but I’ve been in several DC power failures where the fault was in the transfer switch. It sure is nice to have separate failure domains with low enough latency between them to pretty much ignore it in application architectures.
lumost 6y ago
Colos will rarely lose power, but having your line cut due to a backhoe is pretty common. Even in top tier facilities I observed some loss of service every 6-12 months, add in some misconfiguration risk and Colo failure becomes a frighteningly common affair. This can be mitigated through redundant service providers, careful checks on shared interconnects and other measures - but having "hard" failure isolation at the facility level will also get you there with less chance of someone doing something dumb.
m3adow 6y ago
I disagree. AZs are completely independent data centers kilometres apart. For any businesses which may need low latency but still want full HA (e.g. finance systems), it's a blessing. This requirement cannot be fully covered with separate data center regions, something like an airplane crash would still hit everything.
ikiris 6y ago
This kind of thinking is how you end up in a newspaper article where you're in a building in new york babysitting a generator during a hurricane while everyone sane is serving from Atlanta now. You're doing it wrong. Plan to lose sites. If you plan to never lose a building, you're just setting yourself up for pain by optimizing for the wrong kind of redundancy.

closeparen 6y ago

I don’t know about you, but I’ve been in several DC power failures where the fault was in the transfer switch. It sure is nice to have separate failure domains with low enough latency between them to pretty much ignore it in application architectures.

lumost 6y ago

Colos will rarely lose power, but having your line cut due to a backhoe is pretty common. Even in top tier facilities I observed some loss of service every 6-12 months, add in some misconfiguration risk and Colo failure becomes a frighteningly common affair. This can be mitigated through redundant service providers, careful checks on shared interconnects and other measures - but having "hard" failure isolation at the facility level will also get you there with less chance of someone doing something dumb.

m3adow 6y ago

I disagree. AZs are completely independent data centers kilometres apart. For any businesses which may need low latency but still want full HA (e.g. finance systems), it's a blessing. This requirement cannot be fully covered with separate data center regions, something like an airplane crash would still hit everything.

ikiris 6y ago

This kind of thinking is how you end up in a newspaper article where you're in a building in new york babysitting a generator during a hurricane while everyone sane is serving from Atlanta now. You're doing it wrong. Plan to lose sites. If you plan to never lose a building, you're just setting yourself up for pain by optimizing for the wrong kind of redundancy.