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SYSTEM DESIGNDesign a Distributed Lock ServiceGoogleApacheHashiCorp

TRAFFIC LEVEL

—/3

CONSTRAINTS

Lock service nodes5 (Raft quorum)

Lock operations/sec10,000

Lock TTL range1 sec – 30 sec

Network partition toleranceMajority quorum (3/5 nodes)

Leader election time< 1 sec

Compute & Network

Load BalancerDistribute traffic

API GatewayEntry point / auth

API ServerBusiness logic

Worker NodeAsync processing

CDN EdgeGlobal cache

WebSocket GatewayPersistent connections

Data Stores

PostgreSQLRelational DB

MySQLRelational DB

CassandraWide-Column DB

DynamoDBNoSQL / Managed

S3 BucketObject storage

Queues & Cache

Redis CacheIn-memory store

KafkaEvent stream

ZookeeperCoordination

Specialized

Bloom FilterProbabilistic set

Rate LimiterThrottling

Geohash ServiceGeospatial index

Trie ServerPrefix search

APNS / FCMPush notifications

AggregatorBatch / roll-up

Drag to canvas · Hover node for × to delete · Draw from handle to connect

⚡

Design your architecture

Drag components from the left panel · Connect them by drawing from a node handle · Hit Start Simulation to validate

🚨 INCIDENT

GoogleApacheHashiCorp

Design a distributed lock service (like Google Chubby or Apache ZooKeeper). Allow multiple nodes in a cluster to acquire exclusive locks on named resources. Locks must be safe (only one holder at a time), live (no deadlocks), and fault-tolerant (lock service crash doesn't corrupt lock state).

📥 Assigned to:You — Senior Engineer

SCALE LEVELS

1,000 RPS

Target: <10ms

10,000 RPS

Target: <20ms

50,000 RPS

Target: <15ms

GLOBAL SUCCESS RATE

100.0%

P99 LATENCY

45ms

Target: < 200ms

TOTAL RPS INGESTED0 / 11,000