Search the practice set
126 questions, 454 terms and 400 topics in 20 areas.
23 results for “Fault Isolation”
Byzantine Fault
A failure in which a component behaves arbitrarily or deceptively — returning wrong results rather than stopping — as distinct from simply crashing.
Cell Isolation
Bulkheading at the level of a complete system copy, so that any failure — including ones nobody predicted — is contained to the customers assigned to one cell.
Fault Tolerance
Continuing to operate correctly despite the failure of some components, by design rather than by luck.
Thread Pool Isolation
Giving each downstream dependency its own pool of threads or permits, so one slow dependency cannot consume the capacity needed to serve everything else.
Blameless Postmortem
An incident review that seeks the systemic conditions that made a failure possible, explicitly excluding individual fault.
Blast Radius
The set of things that break, or become reachable, when one component fails or is compromised.
Blast Radius Reduction
The set of deliberate partitions — accounts, regions, zones, cells, tenants, deployment stages — that bound how far any single failure or compromise can reach.
Bulkhead
Partitioning resources so that exhaustion caused by one dependency or tenant cannot starve the others.
Cell-Based Architecture
Partitioning a service into complete, independent copies of itself, each serving a subset of customers, so a failure is bounded to one cell.
Microsegmentation
Enforcing fine-grained network policy between individual workloads rather than between broad network zones, so a compromise cannot move laterally.
Monzo's Microservice Estate
Monzo runs a bank on well over a thousand microservices, and the interesting engineering is in the platform and network isolation that makes that number survivable.
Noisy Neighbour
One tenant or workload consuming shared resources to the detriment of others sharing the same infrastructure.
Shuffle Sharding
Assigning each customer a random combination of workers rather than a fixed shard, so that any two customers rarely share their whole set.
Two-Phase Locking
The concurrency control protocol behind serializable isolation — acquire locks in a growing phase, release only in a shrinking phase, never interleaving the two.
Virtual Private Cloud
A logically isolated network inside a cloud provider, with an address range you control and explicit rules for what may enter and leave.
Write Skew
An anomaly where two transactions each read a set of rows, make disjoint writes based on what they read, and together violate an invariant neither could have broken alone.
A service calls four dependencies. How do you size its thread pools, and why is the total often smaller than people expect?
The sizing rule Little's Law, per dependency: concurrency = throughput to that dependency × its latency. Dependency Calls/s Latency Concurrency Pool Auth 500 10
A team proposes circuit breakers on every downstream call. What would you add, and why is the breaker not the most important control?
Why the bulkhead matters more A circuit breaker acts after it has detected a pattern of failure. During the seconds before it trips — and while its threshold is
One customer's batch job saturates a shared service and degrades everyone. Rate limiting them fixes it, until the next customer does the same. What is the structural answer?
Why per customer rate limits keep failing A static limit is set from what that customer was doing, not from what the service can serve. It is reactive — you dis
You are asked to make a multi-tenant SaaS resilient to "any single failure". You propose cells. What must you find before that claim is true?
What must be found: every shared dependency A cell is isolated only if nothing inside it depends on something shared with another cell. The work of adopting the
Fault Isolation
Cells, zones, tenants and the partitions that bound a failure.
Bulkheads & Isolation
Partitioning resources so one dependency cannot starve the others.
Transactions & Isolation
ACID, isolation levels, and the anomalies each level permits.