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Classic designs 6

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3. Design a Distributed Cache
Partition cached data, survive node loss and keep cache misses from overwhelming the source of truth.
ClassicMedium
Caching Sharding Databases
+9
Distributed systems AWS Consistency Consistent hashing Hot keys LRU eviction Memcached Redis Replication
Worked design
Practice
67. Design for Write Scale: A Million Writes a Second
A live TV vote at a million writes a second: spread by key, buffer in Kafka, aggregate the hot counter in two stages, shed what can wait.
ClassicMedium
Sharding Databases Streaming
+6
Distributed systems AWS DynamoDB Flink Kafka Scaling writes
Worked design
Practice
70. Design an In-Memory Data Store like Redis
An in-memory data store like Redis, from one event loop to Redis Cluster to a durable platform.
ClassicMedium
Caching Sharding Databases
+5
Distributed systems AWS In memory Redis Replication
Worked design
Practice
71. Design a Search Engine like Elasticsearch
Search a billion documents in 200 ms: inverted indexes, analysers, Lucene segments, shards and replicas, query then fetch with BM25, fed by CDC.
ClassicMedium
Sharding Search Distributed systems
+4
AWS Inverted index Lucene OpenSearch
Worked design
Practice
75. Design a Key-Value Store like DynamoDB
A key-value store like DynamoDB, from one durable node to Paxos-replicated partitions to global tables run for thousands of tenants.
ClassicMedium
Sharding Databases Distributed systems
+5
AWS DynamoDB Key value store NoSQL Replication
Worked design
Practice
89. Design a Donations Website for a Charity Event
Ten charities, three days, $100 M: charge through a third-party processor exactly once, queue the broadcast spikes, keep live totals on sharded counters. One-hour boards for junior, senior and staff, with the theory behind them.
ClassicMedium
Sharding Queues Databases
+6
Distributed systems AWS DynamoDB Idempotency Payments Reconciliation
Worked design
Practice

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Classic designs 6

3. Design a Distributed Cache

67. Design for Write Scale: A Million Writes a Second

70. Design an In-Memory Data Store like Redis

71. Design a Search Engine like Elasticsearch

75. Design a Key-Value Store like DynamoDB

89. Design a Donations Website for a Charity Event