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[��]ǰ��΢��һ��ϵͳ��ϣ��ܶ༼��Ѷ��ȽϹ��ģ��е�ԭ�򲻻ᳬ��James Hamilton��On Designing and Deploying Internet-Scale Service(1)��Ǽ��Χ��James��һ��“Design for fai...

ǰ��΢��һ��ϵͳ��ܶ༼��Ѷ��ȽϹ��ģ��е�ԭ�򲻻ᳬ��James Hamilton��On Designing and Deploying Internet-Scale Service(1)��Ǽ��Χ��James��һ��“Design for failure”��л��ܹ��ɹ��һ��ؼ��ϵͳ�Ĺ��ʵ�ǳ��򵥣�James paper��ݼ��Ʋ��ۣ��Ƕ��ʵ��ÿ��˾��Щ��⼰ִ��˼ܹ��ɰܡ�

��⻰˵�꣬��о��Redis��ȥ��һ��MemcacheDB, Tokyo Tyrant, Redis performance test��ĿǰΪֹ��benchmark��Ȼ��Ч��1��Ǿ��˺ܶ��ۻ��ҵ�key value�洢��Ʒ��ջ󣬴�Cassandra�ĵ��(Twitter��ͣ��ҵ��ʹ��)��HBase��(Facebook�µ��ҵ��ѡ��HBase(2))��ٻ�ͷ��ȥ��Redis��ֻ��1��Դ��ĳ��漰��δ��ھ��ԡ�Redis��ܾ��ˣ��ǰʮ��վ��Ӳ�Ʒ��1̨Redis�Ϳ��洢��Cache��󡣳��ӡ��֮�⣬ҵ��ʵ�ձ��Redis��ʶ��һ��һЩ�۵㹩��̽�֡�

1. Redis��ʲô

��Ľ��Ӱ��ô��Redis��ΪRedis��һ��key value store, �ǿ��ܻ��MySQL��Ϊ��һ��Գ־û��cache, ��ֻ��һЩƵ��ʵ��ʱ��ݡ�Redis��REmote DIctionary Server��д��Redis�ڹٷ��վ�ĵĸ��A persistent key-value database with built-in net interface written in ANSI-C for Posix systems��ƫ��key value store��һЩ��ΪRedis��һ��memory database��Ϊ��ĸ��ܶ��ǻ��ڴ��Ļ��һЩ��ΪRedis��һ��data structure server��ΪRedis֧�ָ��ӵ��ԣ��List, Set�ȡ��Redis��õĲ�ͬ��Redis��ʹ�÷�ʽ��

��Ŀǰ��ʹ��ַ�ʽ��洢��ϵ��ݿ��key value��Щ��ҵ��ͣ��û��ữƽ̨�еĹ�ϵ��һ��list��Ҫ�ù�ϵ��ݿ��洢��Ҫת��һ�ֶ��м�¼��ʽ��ʽ��ںܶ��ݣ�ÿһ��Ҫ�洢һЩ�ظ��Ϣ��key value�洢��޸ĺ�ɾ��Ƚ��鷳��Ҫ��ȫ��ݶ��д�롣Redis��ڴ��˸��ͣ��ҵ��ܹ��ԭ�ӵķ��Щ��ݽṹ��Ҳ��Ҫ��ĳ־ô洢��⣬�Ӽܹ��Ͻ��ǰ��ִ洢��Ҫ��һЩ��·��⡣

2. Redis��ܱ�Memcache��

�ܶ࿪��߶��ΪRedis��ܱ�Memcached�죬Memcached��ȫ��ڴ棬��Redis��г־û��ԣ��ʹ��첽�ģ�RedisҲ��ܱ�Memcached�졣��ǲ��Խ��Redisռ��ơ�һֱ��˼��ԭ��Ŀǰ�뵽��ԭ��⼸��档

Libevent��Memcached��ͬ��Redis��û��ѡ��libevent��LibeventΪ��ӭ��ͨ��ɴ��Ӵ�(ĿǰRedis��뻹��libevent��1/3)��ض�ƽ̨�Ĳ��ܡ�Redis��libevent��ļ��޸�ʵ��Լ��epoll event loop(4)��ҵ�粻�ٿ��Ҳ��Redisʹ��һ��libevent��libev��߻��Ǽ��RedisӦ��С�ɲ�ȥ��˼·��һ��ӡ��̵�ϸ��Ǳ��Redis֮ǰ��Ҫִ��./configure��
CAS��⡣CAS��Memcached�бȽϷ��һ�ַ�ֹ��޸��Դ�ķ��CASʵ��ҪΪÿ��cache key��һ��ص�cas token��cas�൱value�汾�ţ�ÿ��set��token��Ҫ��˴��CPU��ڴ��˫�ؿ��Ȼ��Щ��С��ǵ��10G+ cache�Լ�QPS��֮��Щ��ͻ��˫��Դ��һЩϸ΢��ܲ��(5)��

3. ��̨Redis�Ĵ��ݱ��ڴ�С

Redis��ȫ��ڴ��˸��ٵ��ܣ��Ҳ��һЩ��֮��һ��վ��100��ע��û��Щ��Ҫ��Redis��洢��ڴ��ܹ��100��û��ҵ��ʵ��100��û�ֻ��5��Ծ�û��1��ʹ�1�ε�Ҳֻ��15��û��ȫ��100��û��ݶ��ڴ��в��֮��RAM��ҪΪ��򵥡�

��ϵͳ�ǳ��ƣ��ϵͳ��Ӧ�÷��ʵ��ݶ��ڴ棬��ڴ��ɲ��µ��ݣ��ϵͳ��ܽ��ֳ��û�з��ʵ��ݽ��̣�Ϊ�µ�Ӧ��ռ䡣�ִ��ϵͳ��Ӧ��ṩ�Ĳ��ڴ棬��ڴ�(Virtual Memory)�ĸ��

��ͬ�Ŀ��ǣ�Redis 2.0Ҳ��VM��ԡ��Redis��ͻ��ڴ��ơ��ʵ��ȷ��롣

4. Redis��VMʵ��ظ��

Redis��VM��֮ǰ��epollʵ��˼·��Լ�ʵ�֡��ǰ��ϵͳ�Ľ��ᵽOSҲ��Զ��ʵ��ݷ��룬Redisֻ��ҪOS��һ��ڴ棬OS��Զ��ݷ��ڴ棬��ݽ��Ӳ�̣��һ��֪��“��ִ��ϵͳ(3)”��Varnish��ʵ�֣�Ҳȡ��˷ǳ��ɹ��Ч��

��antirez�ڽ��ΪʲôҪ�Լ�ʵ��VM��ᵽ��ԭ��(6)��ҪOS��VM��뻻��ǻ��Page����OS VM1��Page��4K, 4K��ֻҪ��һ��Ԫ�ؼ�ʹֻ��1��ֽڱ��ʣ��ҳҲ��ᱻSWAP, ��Ҳͬ��һ��ֽڿ��ܻỻ��4K��õ��ڴ档��Redis�Լ�ʵ��Դﵽ��ƻ��ȡ��ʲ��ϵͳSWAP�ڴ��ʱblock��̣�Ҳ�ǵ��RedisҪ�Լ�ʵ��VMԭ��֮һ��

5. ��get/set��ʽʹ��Redis

��Ϊһ��key value��ڣ��ܶ࿪��Ȼ��ʹ��set/get��ʽ��ʹ��Redis��ʵ��Ⲣ��Ż��ʹ�÷��δ��VM��£�Redisȫ��Ҫ��ڴ棬��Լ�ڴ��Ҫ��

��һ��key-value��Ԫ��Ҫ��Сռ��512�ֽڣ��ʹֻ��һ��ֽ�Ҳռ��512�ֽڡ��ʱ��һ��ģʽ��԰�key��ã��key-value��һ��key�У�value��Ϊһ��set��룬��ͬ��512�ֽھͻ��10-100��

��Ϊ�˽�Լ�ڴ棬��ʹ��hashset��set/get�ķ�ʽ��ʹ��Redis��ϸ��ο��(7)��

6. ʹ��aof��snapshot

Redis��ִ洢��ʽ��Ĭ��snapshot��ʽ��ʵ�ַ��Ƕ�ʱ��ڴ��Ŀ��(snapshot)�־û��Ӳ�̣��ַ��ȱ��ǳ־û�֮��crash��ᶪʧһ��ݡ��ߵ��ƶ��aof��ʽ��aof��append only mode��д��ڴ��ݵ�ͬʱ���浽��־�ļ��һ��ϵͳ�У��־��һ��ǳ��Ӵ��ݣ��ά��ɱ��ǳ��ߣ��ָ��ؽ�ʱ��ǳ��ʧȥaof�߿��Ա��⡣��Ҫ��Redis��һ��ڴ��ݽṹģ�ͣ��е��ƶ��ǽ��ڶ��ڴ渴��ݽṹ��Ч��ԭ�Ӳ��ϣ��Ϳ��aof��һ��ǳ��Э��Ĳ��֡�

��ʵaofĿ��Ҫ��ݿɿ��Լ��߿��ԣ��Redis��һ�ַ��ﵽĿ�ģ�Replication��Redis�ĸ��ܣ��ƻ��û��ӳ١��ﵽ�˷�ֹ��ϼ�ʵ��˸߿��á�

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Ҫ��ɹ�ʹ��һ�ֲ�Ʒ��Ҫ��˽��ԡ�Redis��ͻ��ܹ��ļ�Ԧ��Թ��ںܶ��Ӧ�þ��кܴ��ϣ��ͬ�м��뵽Redisʹ�ü��о��С�

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On Designing and Deploying Internet-Scale Service(PDF)
Facebook’s New Real-Time Messaging System: HBase To Store 135+ Billion Messages A Month
What’s wrong with 1975 programming
Linux epoll is now supported(Google Groups)
CAS and why I don’t want to add it to Redis(Google Groups)
Plans for Virtual Memory(Google Groups)
Full of keys(Salvatore antirez Sanfilippo)

-EOF-

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