redis是什麼？

Redis is an open source, BSD licensed, advanced key-value store. It is often referred to as a data structure server since keys can contain strings, hashes, lists, sets and sorted sets.
redis是開源,BSD許可,高階的key-value儲存系統，可以用來儲存字串,雜湊結構,連結串列,集合,因此,常用來提供資料結構服務。

redis和memcached相比,的獨特之處：

1、redis可以用來做儲存(storge), 而memccached是用來做快取(cache)
這個特點主要因為其有”持久化”的功能；
2、 儲存的資料有”結構”,對於memcached來說,儲存的資料,只有1種類型–”字串”,
而redis則可以儲存字串,連結串列,雜湊結構,集合,有序集合。

Redis下載及編譯：

1、 官方站點：http://redis.io/，下載最新版或stable版（當前為 Redis 3.0.5 is the latest stable version：http://download.redis.io/releases/redis-3.0.5.tar.gz）；
2、解壓原始碼並進入目錄：cd redis-3.0.5；
3、不用configure，原始碼是官方configure過的,但官方configure時,生成的檔案有時間戳資訊,Make只能發生在configure之後如果你的虛擬機器的時間不對,比如說是2012年,解決: date -s ‘yyyy-mm-dd hh:mm:ss’重寫時間，再 clock -w 寫入cmos；
4、直接make，如果是32位機器，採用make 32bit；
5、可選步驟: make test 測試編譯情況，可能出現如下情況：

[[email protected] redis-3.0.5]$ make test
cd src && make test
make[1]: 進入目錄“/opt/redis-3.0.5/src”
You need tcl 8.5 or newer in order to run the Redis test
make[1]: *** [test] 錯誤 1
make[1]: 離開目錄“/opt/redis-3.0.5/src”
make: *** [test] 錯誤 2

通過安裝tcl解決（yum install tcl）；
6、安裝到指定目錄，如/usr/local/redis

make  PREFIX=/usr/local/redis install

注意：PREFIX必需為大寫
7、make install之後,得到如下幾個檔案

8、將原始碼中redis.conf拷貝到/usr/local/redis目錄；

啟動並測試

1、進行後臺啟動：修改redis.conf中“daemonize no”為“daemonize yes”

./bin/redis-server redis.conf

2、檢視啟動日誌：vi redis.log

11020:M 14 Dec 19:48:01.026 # You requested maxclients of 10000 requiring at least 10032 max file descriptors.
11020:M 14 Dec 19:48:01.026 # Redis can't set maximum open files to 10032 because of OS error: Operation not permitted.
11020:M 14 Dec 19:48:01.026 # Current maximum open files is 4096. maxclients has been reduced to 4064 to compensate for low ulimit. If you need higher maxclients increase 'ulimit -n'.
                _._
           _.-``__ ''-._
      _.-``    `.  `_.  ''-._           Redis 3.0.5 (00000000/0) 64 bit
  .-`` .-```.  ```\/    _.,_ ''-._
 (    '      ,       .-`  | `,    )     Running in standalone mode
 |`-._`-...-` __...-.``-._|'` _.-'|     Port: 6379
 |    `-._   `._    /     _.-'    |     PID: 11020
  `-._    `-._  `-./  _.-'    _.-'
 |`-._`-._    `-.__.-'    _.-'_.-'|
 |    `-._`-._        _.-'_.-'    |           http://redis.io
  `-._    `-._`-.__.-'_.-'    _.-'
 |`-._`-._    `-.__.-'    _.-'_.-'|
 |    `-._`-._        _.-'_.-'    |
  `-._    `-._`-.__.-'_.-'    _.-'
      `-._    `-.__.-'    _.-'
          `-._        _.-'
              `-.__.-'

11020:M 14 Dec 19:48:01.027 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
11020:M 14 Dec 19:48:01.027 # Server started, Redis version 3.0.5
11020:M 14 Dec 19:48:01.027 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
11020:M 14 Dec 19:48:01.027 # WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue run the command 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' as root, and add it to your /etc/rc.local in order to retain the setting after a reboot. Redis must be restarted after THP is disabled.
11020:M 14 Dec 19:48:01.027 * DB loaded from disk: 0.000 seconds
11020:M 14 Dec 19:48:01.027 * The server is now ready to accept connections on port 6379

3、啟動客戶端連線並測試：

[[email protected] redis]$ ./bin/redis-cli 
127.0.0.1:6379> set test redis
OK
127.0.0.1:6379> get test
"redis"
127.0.0.1:6379>

到此redis編譯、安裝及測試完全通過；