Load Balancing Building Blocks

on YouTube ↗39m

" summary

Facebook runs a seven-layered chain of load balancers per request (DNS → POPs → L4 → L7 → backends) and uses DNS steering plus a tool called cartographer to spill over capacity across regions. DNS TTLs are misleading (1 minute TTL yields ~50% sticky traffic after 10 minutes). POPs cut round-trip setup from ~450ms to ~90ms even for dynamic requests by keeping long-lived connections. Global L4 aggregation uses maglev hashing with converged health checks and direct responses; the open source implementation is catran and it operates at Facebook scale.

AI-written summary · about

" chapters (7)

1. 0:00Introduction to load balancing
2. 3:46Layer 4 and 7 balancers
3. 8:08DNS load balancing
4. 14:59Points of presence (POPs)
5. 19:44Global traffic management
6. 22:31Maglev and software load balancing
7. 33:39System integration and Q&A

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