redis主從複製 原文地址：http://www.ttlsa.com/archives/215
redis安裝配置參見:ubuntu下redis安裝配置 http://www.ttlsa.com/archives/184
一.redis主從複製特點:
1.master可以擁有多個slave
2.多個slave可以連接同一個master外，還可以連接到其他slave
3.主從複製不會阻塞master，在同步數據時，master可以繼續處理client請求
4.提高系統的伸縮性
5.可以在master禁用數據持久化，註釋掉master配置文件中的所有save配置，只需在slave上配置數據持久化
二.redis主從複製過程:
當配置好slave後，slave與master建立連接，然後發送sync命令。無論是第一次連接還是重新連接，master都會啓動一個後臺進程，將數據庫快照保存到文件中，同時master主進程會開始收集新的寫命令並緩存。後臺進程完成寫文件後，master就發送文件給slave，slave將文件保存到硬盤上，再加載到內存中，接着master就會把緩存的命令轉發給slave，後續master將收到的寫命令發送給slave。如果master同時收到多個slave發來的同步連接命令，master只會啓動一個進程來寫數據庫鏡像，然後發送給所有的slave。
三.redis主從配置:
配置具體參數含義參見: http://www.ttlsa.com/archives/184
【master】
daemonize yes
pidfile /var/run/redis.pid
port 6379
timeout 300
loglevel verbose
logfile /usr/local/redis-2.2.12/var/log/redis.log
databases 16
save 900 1
save 300 10
save 60 10000
rdbcompression yes
dbfilename dump.rdb
dir /usr/local/redis-2.2.12/var/data
requirepass redis
appendonly no
appendfsync everysec
no-appendfsync-on-rewrite no
slowlog-log-slower-than 10000
slowlog-max-len 1024
vm-enabled no
vm-swap-file /tmp/redis.swap
vm-max-memory 0
vm-page-size 32
vm-pages 134217728
vm-max-threads 4
hash-max-zipmap-entries 512
hash-max-zipmap-value 64
list-max-ziplist-entries 512
list-max-ziplist-value 64
set-max-intset-entries 512
activerehashing yes
【slave】
daemonize yes
pidfile /var/run/redis.pid
port 6379
timeout 300
loglevel verbose
logfile /usr/local/redis-2.2.12/var/log/redis.log
databases 16
save 900 1
save 300 10
save 60 10000
rdbcompression yes
dbfilename dump.rdb
dir /usr/local/redis-2.2.12/var/data
appendonly no
appendfsync everysec
no-appendfsync-on-rewrite no
slowlog-log-slower-than 10000
slowlog-max-len 1024
vm-enabled no
vm-swap-file /tmp/redis.swap
vm-max-memory 0
vm-page-size 32
vm-pages 134217728
vm-max-threads 4
hash-max-zipmap-entries 512
hash-max-zipmap-value 64
list-max-ziplist-entries 512
list-max-ziplist-value 64
set-max-intset-entries 512
activerehashing yes
slaveof 192.168.1.189 6379
masterauth redis
四.redis複製測試
查看master端日誌:
[8930] 31 Jul 19:16:09 - Accepted 192.168.1.136:54774
[8930] 31 Jul 19:16:09 * Slave ask for synchronization
[8930] 31 Jul 19:16:09 * Starting BGSAVE for SYNC
[8930] 31 Jul 19:16:09 * Background saving started by pid 10782
[10782] 31 Jul 19:16:09 * DB saved on disk
[8930] 31 Jul 19:16:09 * Background saving terminated with success
[8930] 31 Jul 19:16:09 * Synchronization with slave succeeded
[8930] 31 Jul 19:16:14 - DB 0: 1 keys (0 volatile) in 4 slots HT.
[8930] 31 Jul 19:16:14 - 1 clients connected (1 slaves), 807320 bytes in use
查看slave端日誌:
[24398] 01 Aug 10:16:10 * Connecting to MASTER...
[24398] 01 Aug 10:16:10 * MASTER <-> SLAVE sync started: SYNC sent
[24398] 01 Aug 10:16:10 * MASTER <-> SLAVE sync: receiving 25 bytes from master
[24398] 01 Aug 10:16:10 * MASTER <-> SLAVE sync: Loading DB in memory
[24398] 01 Aug 10:16:10 * MASTER <-> SLAVE sync: Finished with success
[24398] 01 Aug 10:16:15 - DB 0: 1 keys (0 volatile) in 4 slots HT.
[24398] 01 Aug 10:16:15 - 1 clients connected (0 slaves), 798960 bytes in use
master端操作:
redis 127.0.0.1:6379> set k_m master
OK
slave端操作:
redis 127.0.0.1:6379> get k_m
"master"