TLDR Tech / Data
How Vercel Migrated Its Build Database
Vercel successfully migrated the state of its build warm pool from Redis to DynamoDB, prioritizing durable storage for critical billing and container mappings. This transition involved using techniques like dual writes, shadow reads, feature flags, and production comparisons to ensure a safe cutover. A key challenge was adapting to DynamoDB after relying on Redis's ultra-low latency, which necessitated a redesign of the supply loop to focus on concurrency over serialized reads.
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