2020MIT 6.824分布式系统笔记（三）
2021-01-31 本文已影响0人
加油11dd23
一、Big Storage
- 为big storage system设计一个接口
- how to design innards of the storage system
1. WHY HARD
- performance -> sharding(分片)
- faults -> tolerance
- tolerance -> replication
- replication -> inconsistency
- consistency -> low performance
2. STRONG CONSISTENCY
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单个服务器的容错能力很差
3. BAD REPL DESIGN
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4.1 GFS
- Big, Fast
- Global
- sharding
- Automatic recovery
4.2 Single data center
- Intern use
- Big sequential access
- single master
4.3 master data细节讲解
image.png
- filename -> array of chunk handles(NV非易失存储)
- handle ->
1.list of chunk server(V)
2.version number for each chunk(NV)
3.primary(V)
4.lease expiration(V) - LOG, CHECKPOINT -> DISK
4.4 master opration细节讲解
- READ
1.name,offset -> master
2.M chunk handle, serverlist
cached
3.c(line) -> cs(chunk server) - WRITES
- NO PRIMATY? on master
find up to date repl
pick p , s
increment v#
tells p , s v#
M writers v# k, dish
