Search the practice set
126 questions, 454 terms and 400 topics in 20 areas.
60 results for “Single vs Multi-Region”
Active-Active vs Active-Passive
Whether all regions serve traffic simultaneously, or one serves while another waits to take over — a choice about which failure mode you would rather have.
Multi-Factor Authentication
Requiring evidence from more than one category — something you know, have, or are — so a single stolen credential is insufficient.
Multi-Leader Replication
Accepting writes at more than one node and replicating between them, which removes the single-primary bottleneck and introduces write conflicts.
Salesforce's Metadata-Driven Multi-Tenancy
Salesforce serves every customer from shared infrastructure with a single physical schema, storing customer-specific data structures as metadata rather than as separate tables.
Availability Zone
One or more physically separate data centres inside a cloud region, with independent power, cooling and network, connected by low-latency links.
Data Residency
A requirement that specific data be stored and sometimes processed only within a defined geography.
Global Traffic Management
The layer that decides which region a given user reaches, using DNS, anycast or an edge network, and that performs regional failover.
Regional Evacuation
The deliberate, rehearsed act of shifting all traffic out of a region — treated as a routine operation rather than an emergency procedure.
Build vs Buy
The choice between developing a capability in-house and acquiring it, decided on differentiation and total cost rather than on feature lists.
Containment vs Eradication
Stopping an attacker's ongoing access versus removing their foothold entirely — sequential phases with different urgency and different risks of doing them wrong.
Cost vs Reliability Trade-off
The non-linear relationship between availability and spend, which makes each additional nine roughly an order of magnitude more expensive.
Delivery vs Maintainability
Choosing where to take deliberate shortcuts, based on which kinds of debt are cheap to repay and which compound.
Durability vs Availability
Two different storage guarantees — whether data survives, and whether it can be reached right now — routinely conflated because both are quoted in nines.
ETL vs ELT
Whether data is transformed before loading into the target or after it, which decides where the compute happens and how much raw history you keep.
Fail-Fast vs Fail-Safe
Whether a component should stop immediately on detecting a problem, or continue in a degraded but safe mode — a choice that depends entirely on which outcome is worse.
Horizontal vs Vertical Scaling
Adding more machines versus making one machine bigger — and the fact that vertical is underrated for stateful tiers.
Layer 4 vs Layer 7 Load Balancing
Balancing on connection metadata (IP and port) versus on the content of the request (path, host, headers).
Managed vs Self-Managed
Trading control, portability and unit cost against the operational burden of running the thing yourself.
Monolith vs Microservices
A trade of deployment independence against distributed-systems complexity, decided by team topology far more often than by technology.
Multi-Cloud
Deliberately running across more than one cloud provider — a decision with a much higher cost than the lock-in it is usually adopted to avoid.
OLTP vs OLAP
Two workload shapes with opposite requirements — many small indexed transactions versus few large scans and aggregations — which is why they belong in different stores.
Operational vs Analytical Store
The separation between the store serving the application's transactions and the one serving reporting and analysis, and the mechanism connecting them.
Provisioned vs Serverless Capacity
Paying for a fixed database size continuously, versus paying for capacity consumed with automatic scaling — a crossover decision driven by duty cycle.
Re-architect vs Rebuild
Restructuring an existing system incrementally versus writing a replacement from scratch — and the strong evidence that incremental wins.
SQL vs NoSQL
A choice driven by access patterns, consistency requirements and query flexibility — not by data volume, which is the reason usually given.
Security vs Usability
A trade-off that is usually resolved by varying the control with the value of the action, rather than by choosing a uniform level of friction.
Strong vs Eventual Consistency
A per-operation decision, not a per-system one: whether this specific read must reflect every completed write.
Synchronous vs Asynchronous Communication
Whether the caller waits for the callee's answer — decided by whether the caller's outcome depends on it, not by latency or taste.
Synchronous vs Asynchronous Replication
Whether a write is acknowledged only after a replica has it, trading write latency against the amount of data a failure can lose.
Leadership asks for multi-region "for resilience". What do you establish before designing anything?
First: is multi region the right answer to the actual problem? Multi region defends against a region wide failure . Most outages are not that — they are bad dep
The business asks for "multi-region" after a regional outage. Before agreeing, what do you need to establish, and what are you actually signing up for?
What the interviewer is testing Whether you convert a vague requirement into numbers before designing, and whether you know that multi region is primarily a dat
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
You run active-active across two regions. The link between them fails. What should each region do, and what would you have designed differently?
The immediate answer Neither region can safely keep accepting writes to shared state, because neither can know it is the surviving side. Each sees one of two no
A DR test fails: the secondary region cannot launch enough instances. What happened, and what standing checks prevent it?
What happened Service quotas in the secondary region are far lower than in the primary , because nothing has ever run there at scale. Quotas are per account and
A multi-tenant SaaS product has outgrown one database. You must shard. How do you choose the partition key, and what makes this decision so expensive to get wrong?
What the interviewer is testing Whether you exhaust cheaper options first, and whether you understand that a shard key is close to irreversible. First: do not s
Design the network layout for a three-tier application in one cloud region. What are the decisions you cannot easily change later?
What the interviewer is testing Whether you know which network decisions are cheap and which are effectively permanent. This is a knowledge question with a clea
In July 2019 a single regex deployed globally took Cloudflare's network to 100% CPU within seconds. What does this say about how configuration should be released?
The case, as publicly reported On 2 July 2019, Cloudflare deployed a new managed WAF rule. It contained a regular expression that caused catastrophic backtracki
Single vs Multi-Region
Driven by RTO, RPO and residency rather than by ambition.
Multi-Region Architecture
Surviving a region, and the data consistency price of doing so.
Build vs Buy
Differentiation versus table stakes, priced over five years.
Build vs Buy
Differentiation, five-year TCO, and the exit cost of each option.
Centralised vs Distributed
Shared platform leverage against team autonomy.
Cost vs Reliability
Each nine costing an order of magnitude, and pricing the failure instead.
Delivery vs Maintainability
Fast in the cheap places, careful in the expensive ones.
Functional vs Non-Functional
Behaviour versus quality of behaviour, and why only the second constrains structure.
Horizontal vs Vertical Scaling
Scale out for stateless, scale up first for stateful.
Layer 4 vs Layer 7
Connection-level versus request-level balancing, and what each unlocks.
Managed vs Self-Managed
Trading control and unit cost against operational attention.
Monolith vs Microservices
A team-topology decision far more often than a technology one.
Multi-Agent Systems
Coordination, hand-off and whether more agents actually help.
Multi-Cloud
Best-of-breed, portfolio and portable — three very different costs.
Orchestration vs Choreography
A coordinator that knows the flow, or services that react to events.
Performance vs Cost
Buying latency, and knowing what the last millisecond is worth.
Rebuild vs Re-architect
Why greenfield replacement fails, and the narrow cases where it does not.
Reliability vs Complexity
Mechanisms that add availability and add failure modes.
SQL vs NoSQL
Decided by access patterns and query flexibility, not by data volume.
Security vs Usability
Varying control by the value of the action rather than uniformly.
Serverless vs Containers
Spiky and event-driven versus sustained throughput.
Strong vs Eventual Consistency
A per-operation decision, resolved by what a stale read would cost.
Sync vs Async
Whether the caller's outcome depends on the callee's response.