Search the practice set
126 questions, 454 terms and 400 topics in 20 areas.
28 results for “Storage Costs”
Block Storage
A virtual disk attached to one instance at a time, presented as raw blocks and formatted with a filesystem — the storage databases and stateful workloads run on.
Object Storage
Flat, HTTP-addressable storage for immutable blobs with rich metadata — effectively unlimited, cheap, and not a filesystem.
Storage Tiering
Moving data between access tiers as it cools, so rarely-read data is not paying hot-storage prices.
Bloom Filter
A compact probabilistic structure that answers "is this key definitely absent, or possibly present?" — no false negatives, tunable false positives.
Data Lakehouse
A pattern that puts warehouse-style transactions, schema and governance on top of cheap open-format object storage.
Database Index
A secondary structure that lets the engine find rows without scanning, trading write cost and storage for read speed.
Dropbox's Move Off S3
Dropbox moved the majority of its file storage off Amazon S3 onto custom infrastructure, reporting savings that its S-1 filing put at roughly $75 million over two years.
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.
Egress Path Analysis
Tracing where data physically moves in an architecture, because transfer charges follow paths that appear nowhere on the diagram.
Instance Family
A group of instance types sharing a resource profile — general purpose, compute optimised, memory optimised, storage optimised, accelerated — chosen by which resource the workload…
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.
Open Table Format
A metadata layer over files in object storage that supplies ACID transactions, schema evolution and time travel — the thing that turns a data lake into a lakehouse.
Partial Index
An index built over only the rows matching a predicate, so it is far smaller and cheaper to maintain than a full index.
Pod
The smallest deployable unit in Kubernetes — one or more containers that share a network namespace, storage volumes and a lifecycle, scheduled together on one node.
Trade-off Analysis
Making the costs of an architectural choice explicit and comparable, rather than presenting a recommendation as if it were free.
Choose storage for four workloads: a Postgres data directory, user-uploaded images, a shared build cache, and seven years of audit records.
Postgres data directory — block storage It needs low latency random reads and writes and a filesystem, and it attaches to one instance. That is precisely block
Netflix built its own CDN; Dropbox moved storage off S3. Both are usually wrong. What conditions made them right, and how do you test for those conditions?
What the interviewer is testing Whether you can extract the conditions from a famous decision rather than the decision itself. These two cases are the most comm
PCI DSS assessment covers 40 systems and costs a fortune annually. How would you reduce that architecturally?
The principle Scope follows the data. Any system that stores, processes or transmits cardholder data is in scope and inherits the full control set. Reducing sco
Design a URL shortener handling 100 million new links per month and 10 billion redirects. Where is the real difficulty?
What the interviewer is testing The classic warm up. What is being assessed is not whether you can shorten a URL — it is whether you do capacity arithmetic befo
Storage Costs
Tiering, lifecycle policies, retrieval charges and minimum durations.
Cloud Storage
Object, block and file storage, and the access patterns each suits.
Licence & Vendor Costs
Per-core, per-seat and per-environment terms that shape designs.
Network & Egress Costs
Cross-zone and cross-region transfer that appears on no diagram.
Cost Allocation
Tagging enforced at provisioning, and apportioning shared costs.
Data Lakes & Lakehouses
Open formats on object storage with transactional metadata on top.
Event Sourcing
Storing the change log as the system of record, and what that costs forever.
Multi-Cloud
Best-of-breed, portfolio and portable — three very different costs.
Trade-off Analysis
Making costs explicit and comparable rather than asserting a preference.