一、outline

what is distrubuted system

• parallelism
• fault tolerance
• physical
• security

challenges

• concurrency
• partial failture
• performance

Infraustructure ---abstractions

• storage (look like non-distributed)
• communication
• computation

Implementation

remote procedure core(RPC), threads, concurrency CH(locks)

performance

• scalability -> 2x computers == 2x throughput

  
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fault tolerance

• availability
• recoverability

---

• non volatile storage
• replication

consistency

• put(k,v)

• get(k) -> v

  
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• strongly
• weak

二、Mapreduce

image.png image.png

三、dicussion

• iteration
• stream data
• GFS
• aviod network