SYSTEM DESIGNDesign Dropbox (File Sync)DropboxGoogleBox
TRAFFIC LEVEL
—/3
CONSTRAINTS
Users100M
Avg storage/user5 GB
Total storage500 PB
Block size4 MB
Daily uploads5M files
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
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🚨 INCIDENT
DropboxGoogleBox

Design a file synchronization service like Dropbox. Users upload files from desktop clients, which sync across all their devices. Support 100M users, files up to 5GB, delta sync (only upload changed blocks), and offline editing.

📥 Assigned to:You — Mid Engineer
SCALE LEVELS
1
50,000 RPS
Target: <200ms
2
500,000 RPS
Target: <500ms
3
1,000,000 RPS
Target: <100ms
GLOBAL SUCCESS RATE
100.0%
P99 LATENCY
45ms
Target: < 200ms
TOTAL RPS INGESTED0 / 11,000
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