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Inty Saez Mosquera
Inty Saez Mosquera

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Designing Resilient Systems: From Failure Domains to Long-Lived Software

Modern software systems fail.

Not sometimes — constantly.

Nodes disappear. Networks partition. Dependencies degrade. Humans make mistakes.

Yet most systems are still designed as if stability were the default state.

At Unsink, we start from the opposite assumption:

Failure is normal.


Resilience is not scalability

Scalability answers the question:

“How much load can this system handle?”

Resilience answers a deeper one:

“How does this system behave when parts of it stop working?”

A resilient system:

  • tolerates partial failure
  • degrades gracefully
  • remains observable under stress
  • recovers without human heroics

These properties are architectural — not operational.


Failure domains first

Every system has failure domains:

  • network zones
  • services
  • databases
  • humans

Designing resilience means explicitly modeling these domains and preventing failure from cascading across them.

Boundaries matter.

Isolation matters.

Assumptions kill.


Observability is architecture

Logging is not observability.

Metrics are not observability.

Observability means being able to understand system behavior from the outside — especially during degradation.

If you cannot see your system under stress, you do not control it.

At Unsink, observability is treated as a first-class architectural concern.


Capability-first thinking

Most teams design from tools forward.

We design from outcomes backward.

What capability must exist?

What constraints apply?

What failure modes are acceptable?

Only then do technologies enter the conversation.


Unsink

Unsink is a resilience-first digital studio focused on designing fault-tolerant software systems and long-lived architectures.

We work with organizations that care about:

  • distributed systems
  • graceful degradation
  • SRE-informed engineering
  • cognitive software architecture

You can learn more at:

https://unsink.io

Open technical patterns:

https://github.com/unsinkio/unsink-resilience-patterns


Resilient systems are not accidental.

They are designed.

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