Redis入門：分佈式存儲

Redis入門：分佈式存儲

要完成數據的分片存儲，需要多個redis實例。

1 多個REDIS實例

前面的單個redis節點實例的啓動時默認配置端口號6379。

1.1 配置文件

配置文件位置：/redis根目錄/redis.conf。

修改配置文件，使用vim命令進行編輯：

vim redis.conf

1.1.1 內存分配

一個redis實例默認佔用所有物理內存，在實際使用中需要限制大小。這裏爲了簡化操作，不做內存佔用的配置，使用默認即可。

從下面這一部分中，就能看出內存配置的方式和配置文件的使用方式，如果要使用配置文件，需要在啓動的時候將配置文件作爲啓動命令的第一個參數。

內存配置寫法不同代表的大小也不同。參照11行到16行。

以下爲本段配置內容詳情：

   1 # Redis configuration file example.
   2 #
   3 # Note that in order to read the configuration file, Redis must be
   4 # started with the file path as first argument:
   5 #
   6 # ./redis-server /path/to/redis.conf
   7 
   8 # Note on units: when memory size is needed, it is possible to specify
   9 # it in the usual form of 1k 5GB 4M and so forth:
  10 #
  11 # 1k => 1000 bytes
  12 # 1kb => 1024 bytes
  13 # 1m => 1000000 bytes
  14 # 1mb => 1024*1024 bytes
  15 # 1g => 1000000000 bytes
  16 # 1gb => 1024*1024*1024 bytes
  17 #
  18 # units are case insensitive so 1GB 1Gb 1gB are all the same.
  19

1.1.2 綁定ip

這個版本的配置文件中，綁定IP的示例從60行到62行都是。

綁定的配置在75行。

以下爲本段配置內容詳情：

  46 ################################## NETWORK #####################################
  47 
  48 # By default, if no "bind" configuration directive is specified, Redis listens
  49 # for connections from all available network interfaces on the host machine.
  50 # It is possible to listen to just one or multiple selected interfaces using
  51 # the "bind" configuration directive, followed by one or more IP addresses.
  52 # Each address can be prefixed by "-", which means that redis will not fail to
  53 # start if the address is not available. Being not available only refers to
  54 # addresses that does not correspond to any network interfece. Addresses that
  55 # are already in use will always fail, and unsupported protocols will always BE
  56 # silently skipped.
  57 #
  58 # Examples:
  59 #
  60 # bind 192.168.1.100 10.0.0.1     # listens on two specific IPv4 addresses
  61 # bind 127.0.0.1 ::1              # listens on loopback IPv4 and IPv6
  62 # bind * -::*                     # like the default, all available interfaces
  63 #
  64 # ~~~ WARNING ~~~ If the computer running Redis is directly exposed to the
  65 # internet, binding to all the interfaces is dangerous and will expose the
  66 # instance to everybody on the internet. So by default we uncomment the
  67 # following bind directive, that will force Redis to listen only on the
  68 # IPv4 and IPv6 (if available) loopback interface addresses (this means Redis
  69 # will only be able to accept client connections from the same host that it is
  70 # running on).
  71 #
  72 # IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES
  73 # JUST COMMENT OUT THE FOLLOWING LINE.
  74 # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  75 bind 127.0.0.1 -::1
  76

1.1.3 保護模式

保護模式不啓動，在實際工作中爲了安全是要啓動的，做測試的過程爲了避免麻煩，可以不啓動。

配置項在94行，只需要更改值即可，yes表示開啓，no表示不開啓。

以下爲本段配置詳情：

  90 # By default protected mode is enabled. You should disable it only if
  91 # you are sure you want clients from other hosts to connect to Redis
  92 # even if no authentication is configured, nor a specific set of interfaces
  93 # are explicitly listed using the "bind" directive.
  94 protected-mode no

1.1.4 默認端口

6379是默認端口(要啓動其他的redis實例需要修改端口)。

98行爲配置信息，port後爲要使用的端口號。

以下是本段配置信息：

  96 # Accept connections on the specified port, default is 6379 (IANA #815344).
  97 # If port 0 is specified Redis will not listen on a TCP socket.
  98 port 6379

1.1.5 連接超時

當客戶端空閒時間達到一小時，就會自動斷開連接。0秒錶示不啓用超時配置。

119行爲此項目配置內容，此項的配置單位爲秒，如果啓用配置爲對應的秒數即可。

以下爲本段配置內容詳情，這裏本人配置了1分鐘：

 118 # Close the connection after a client is idle for N seconds (0 to disable)
 119 # timeout 0
 120 timeout 60

1.1.6 後臺運行

daemonize設置成yes讓redis服務器啓動由守護進程管理，使其後臺執行，不佔用控制檯。其配置在257行。

內容如下：

 252 ################################# GENERAL #####################################
 253 
 254 # By default Redis does not run as a daemon. Use 'yes' if you need it.
 255 # Note that Redis will write a pid file in /var/run/redis.pid when daemonized.
 256 # When Redis is supervised by upstart or systemd, this parameter has no impact.
 257 daemonize yes

1.1.7 pid文件

對應不同的redis實例，pid的文件名稱需要和端口同名。配置在289行。

內容如下：

 277 # If a pid file is specified, Redis writes it where specified at startup
 278 # and removes it at exit.
 279 #
 280 # When the server runs non daemonized, no pid file is created if none is
 281 # specified in the configuration. When the server is daemonized, the pid file
 282 # is used even if not specified, defaulting to "/var/run/redis.pid".
 283 #
 284 # Creating a pid file is best effort: if Redis is not able to create it
 285 # nothing bad happens, the server will start and run normally.
 286 #
 287 # Note that on modern Linux systems "/run/redis.pid" is more conforming
 288 # and should be used instead.
 289 pidfile /var/run/redis_6379.pid

1.1.8 持久化規則

• save 900 1 當900秒以內，至少有1條數據變動，可使flush保存數據到文件。
• save 300 10 當300秒以內，至少10條數據變動，保存文件。
• save 60 10000 當60秒內，有10000條數據變動，保存文件。

保持默認規則即可，也可按照實際需求進行配置。

本人這裏配置了第三種，具體內容如下：

360 ################################ SNAPSHOTTING  ################################
 361 
 362 # Save the DB to disk.
 363 #
 364 # save <seconds> <changes>
 365 #
 366 # Redis will save the DB if both the given number of seconds and the given
 367 # number of write operations against the DB occurred.
 368 #
 369 # Snapshotting can be completely disabled with a single empty string argument
 370 # as in following example:
 371 #
 372 # save ""
 373 #
 374 # Unless specified otherwise, by default Redis will save the DB:
 375 #   * After 3600 seconds (an hour) if at least 1 key changed
 376 #   * After 300 seconds (5 minutes) if at least 100 keys changed
 377 #   * After 60 seconds if at least 10000 keys changed
 378 #
 379 # You can set these explicitly by uncommenting the three following lines.
 380 #
 381 # save 3600 1
 382 # save 300 100
 383 save 60 10000

1.2 其他實例

將剛配置好的配置文件複製2份，分別修改端口號和pid文件名即可。

cp redis.conf redis6380.conf
cp redis.conf redis6381.conf

將拷貝的文件中只修改與端口有關內容port和pid的文件名。

2 啓動REDIS多實例

啓動多實例的命令如下：

redis-server redis.conf(指定啓動文件)

啓動另外兩個節點：

#redis-server redis6380.conf
#redis-server redis6381.conf
#ps -ef|grep redis
root       2822      1  0 15:53 ?        00:00:00 redis-server 127.0.0.1:6379
root       2836      1  0 15:53 ?        00:00:00 redis-server 127.0.0.1:6380
root       2848      1  0 15:53 ?        00:00:00 redis-server 127.0.0.1:6381
root       2868   1697  0 15:53 pts/1    00:00:00 grep --color=auto redis

3 登錄客戶端

指定端口登錄客戶端redis-cli -p [端口號]

#默認登錄
[root@lk7 bin]# redis-cli
127.0.0.1:6379> exit
[root@lk7 bin]# redis-cli -p 6379
127.0.0.1:6379> exit
[root@lk7 bin]# redis-cli -p 6380
127.0.0.1:6380> exit
[root@lk7 bin]# redis-cli -p 6381
127.0.0.1:6381> exit

6380和6381會共享6379的dump.db文件，所以不同的節點實例在同一個機器上運行時，可以修改dump.db指定端口文件。