CAP and you
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Consistency…!Availability…!Messages…!
& You…
CAP!theorem
Consistent “…as if every request was executing on a single node, responding to operations one at a time.”
ACID Compliant
Available “…every request received by a non-failing node
in the system must result in a response.”
Partition Tolerant “…the network will be allowed to lose arbitrarily many messages sent from one node to another”
Pick Any Two!?!! It’s complicated…
Consistent & Partition Tolerant “…it is easy to achieve atomic data and partition
tolerance. The trivial system that ignores all requests meets these requirements.”
Consistent & Available “If there are no partitions, it is clearly possible to
provide atomic, available data.”
Available & Partition Tolerant “If there are no consistency requirements, the
service can trivially return v0, the initial value, in response to every request.”
€
2 ⋅ tmessage + tlocalt-Connected Consistent
What has been neglected? Latency Failure Computation Durability More™
Latency Petite Partitions
the little deaths
When the available consistency exceeds the required availability a choice must be made…
Raising the question, how are business decisions made?
What protocols are used to pass messages in your organization?
Has your organization
chosen consistent, available
or partition tolerant?
In any human interaction, the required amount of communication is inversely proportional to the level of trust…
@bhorowitz
Andrew Clay Shafer @littleidea
work on stuff that matters