Introduction
• Distributed low-latency in-memory key-value stores are emerging
• Predictable response times ~10 µs median, ~60 µs 99.9
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-tile
• Problem: Must migrate data between servers
• Minimize performance impact of migration → go slow?
• Quickly respond to hot spots, skew shifts, load spikes → go fast?
• Solution: Fast data migration with low impact
• Early ownership transfer of data, leverage workload skew
• Low priority, parallel and adaptive migration
• Result: Migration protocol for RAMCloud in-memory key-value store
• Migrates 256 GB in 6 minutes, 99.9
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-tile latency less than 250 µs
• Median latency recovers from 40 µs to 20 µs in 14 s
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