Redis缓存数据库介绍与环境搭建

henda

　　在最近的项目中，有高负载数据量访问需求，在memcached和redis之间做了一下比较，最后选择了redis，主要是觉得redis相比memcached有两点优势：一是因为redis的windows版本用起来比较方便（苦逼的项目不允许用linux系统），二是由于redis的value支持比较多的数据类型（除了String、还有List，HashMap等），使用起来比较灵活。下面介绍下redis的环境搭建。

• 　　redis简介
  

　　Redis 是一个高性能的key-value数据库，据说在Linux 2.6, Xeon X3320 2.5Ghz服务器下可以达到SET操作每秒钟 110000 次，GET操作每秒钟 81000 次。，我更倾向于将它作为缓存服务器，既客户端——缓存——数据库，可以显著提高客户端相应速度。

• 　　windows下部署
  

　　下载windows版redis：
　　https://github.com/MSOpenTech/Redis
　　解压到随便一个目录，创建一个redis.con文件，内容如下：
　　[java] view plaincopy

• 　　# Redis configuration file example
  
• 
  
• 　　# By default Redis does not run as a daemon. Use 'yes' if you need it.
  
• 　　# Note that Redis will write a pid file in /var/run/redis.pid when daemonized.
  
• 　　daemonize no
  
• 
  
• 　　# When run as a daemon, Redis write a pid file in /var/run/redis.pid by default.
  
• 　　# You can specify a custom pid file location here.
  
• 　　pidfile /var/run/redis.pid
  
• 
  
• 　　# Accept connections on the specified port, default is 6379
  
• 　　port 6379
  
• 
  
• 　　# If you want you can bind a single interface, if the bind option is not
  
• 　　# specified all the interfaces will listen for connections.
  
• 　　#
  
• 　　# bind 127.0.0.1
  
• 
  
• 　　# Close the connection after a client is idle for N seconds (0 to disable)
  
• 　　timeout 300
  
• 
  
• 　　# Set server verbosity to 'debug'
  
• 　　# it can be one of:
  
• 　　# debug (a lot of information, useful for development/testing)
  
• 　　# notice (moderately verbose, what you want in production probably)
  
• 　　# warning (only very important / critical messages are logged)
  
• 　　loglevel debug
  
• 
  
• 　　# Specify the log file name. Also 'stdout' can be used to force
  
• 　　# the demon to log on the standard output. Note that if you use standard
  
• 　　# output for logging but daemonize, logs will be sent to /dev/null
  
• 　　logfile stdout
  
• 
  
• 　　# Set the number of databases. The default database is DB 0, you can select
  
• 　　# a different one on a per-connection basis using SELECT  where
  
• 　　# dbid is a number between 0 and 'databases'-1
  
• 　　databases 16
  
• 
  
• 　　################################ SNAPSHOTTING  #################################
  
• 　　#
  
• 　　# Save the DB on disk:
  
• 　　#
  
• 　　#   save  
  
• 　　#
  
• 　　#   Will save the DB if both the given number of seconds and the given
  
• 　　#   number of write operations against the DB occurred.
  
• 　　#
  
• 　　#   In the example below the behaviour will be to save:
  
• 　　#   after 900 sec (15 min) if at least 1 key changed
  
• 　　#   after 300 sec (5 min) if at least 10 keys changed
  
• 　　#   after 60 sec if at least 10000 keys changed
  
• 　　save 900 1
  
• 　　save 300 10
  
• 　　save 60 10000
  
• 
  
• 　　# Compress string objects using LZF when dump .rdb databases?
  
• 　　# For default that's set to 'yes' as it's almost always a win.
  
• 　　# If you want to save some CPU in the saving child set it to 'no' but
  
• 　　# the dataset will likely be bigger if you have compressible values or keys.
  
• 　　rdbcompression yes
  
• 
  
• 　　# The filename where to dump the DB
  
• 　　dbfilename dump.rdb
  
• 
  
• 　　# For default save/load DB in/from the working directory
  
• 　　# Note that you must specify a directory not a file name.
  
• 　　dir ./
  
• 
  
• 　　################################# REPLICATION #################################
  
• 
  
• 　　# Master-Slave replication. Use slaveof to make a Redis instance a copy of
  
• 　　# another Redis server. Note that the configuration is local to the slave
  
• 　　# so for example it is possible to configure the slave to save the DB with a
  
• 　　# different interval, or to listen to another port, and so on.
  
• 　　#
  
• 　　# slaveof  
  
• 
  
• 　　# If the master is password protected (using the "requirepass" configuration
  
• 　　# directive below) it is possible to tell the slave to authenticate before
  
• 　　# starting the replication synchronization process, otherwise the master will
  
• 　　# refuse the slave request.
  
• 　　#
  
• 　　# masterauth
  
• 
  
• 　　################################## SECURITY ###################################
  
• 
  
• 　　# Require clients to issue AUTH  before processing any other
  
• 　　# commands.  This might be useful in environments in which you do not trust
  
• 　　# others with access to the host running redis-server.
  
• 　　#
  
• 　　# This should stay commented out for backward compatibility and because most
  
• 　　# people do not need auth (e.g. they run their own servers).
  
• 　　#
  
• 　　# requirepass foobared
  
• 
  
• 　　################################### LIMITS ####################################
  
• 
  
• 　　# Set the max number of connected clients at the same time. By default there
  
• 　　# is no limit, and it's up to the number of file descriptors the Redis process
  
• 　　# is able to open. The special value '0' means no limts.
  
• 　　# Once the limit is reached Redis will close all the new connections sending
  
• 　　# an error 'max number of clients reached'.
  
• 　　#
  
• 　　# maxclients 128
  
• 
  
• 　　# Don't use more memory than the specified amount of bytes.
  
• 　　# When the memory limit is reached Redis will try to remove keys with an
  
• 　　# EXPIRE set. It will try to start freeing keys that are going to expire
  
• 　　# in little time and preserve keys with a longer time to live.
  
• 　　# Redis will also try to remove objects from free lists if possible.
  
• 　　#
  
• 　　# If all this fails, Redis will start to reply with errors to commands
  
• 　　# that will use more memory, like SET, LPUSH, and so on, and will continue
  
• 　　# to reply to most read-only commands like GET.
  
• 　　#
  
• 　　# WARNING: maxmemory can be a good idea mainly if you want to use Redis as a
  
• 　　# 'state' server or cache, not as a real DB. When Redis is used as a real
  
• 　　# database the memory usage will grow over the weeks, it will be obvious if
  
• 　　# it is going to use too much memory in the long run, and you'll have the time
  
• 　　# to upgrade. With maxmemory after the limit is reached you'll start to get
  
• 　　# errors for write operations, and this may even lead to DB inconsistency.
  
• 　　#
  
• 　　# maxmemory
  
• 
  
• 　　############################## APPEND ONLY MODE ###############################
  
• 
  
• 　　# By default Redis asynchronously dumps the dataset on disk. If you can live
  
• 　　# with the idea that the latest records will be lost if something like a crash
  
• 　　# happens this is the preferred way to run Redis. If instead you care a lot
  
• 　　# about your data and don't want to that a single record can get lost you should
  
• 　　# enable the append only mode: when this mode is enabled Redis will append
  
• 　　# every write operation received in the file appendonly.log. This file will
  
• 　　# be read on startup in order to rebuild the full dataset in memory.
  
• 　　#
  
• 　　# Note that you can have both the async dumps and the append only file if you
  
• 　　# like (you have to comment the "save" statements above to disable the dumps).
  
• 　　# Still if append only mode is enabled Redis will load the data from the
  
• 　　# log file at startup ignoring the dump.rdb file.
  
• 　　#
  
• 　　# The name of the append only file is "appendonly.log"
  
• 　　#
  
• 　　# IMPORTANT: Check the BGREWRITEAOF to check how to rewrite the append
  
• 　　# log file in background when it gets too big.
  
• 
  
• 　　appendonly no
  
• 
  
• 　　# The fsync() call tells the Operating System to actually write data on disk
  
• 　　# instead to wait for more data in the output buffer. Some OS will really flush
  
• 　　# data on disk, some other OS will just try to do it ASAP.
  
• 　　#
  
• 　　# Redis supports three different modes:
  
• 　　#
  
• 　　# no: don't fsync, just let the OS flush the data when it wants. Faster.
  
• 　　# always: fsync after every write to the append only log . Slow, Safest.
  
• 　　# everysec: fsync only if one second passed since the last fsync. Compromise.
  
• 　　#
  
• 　　# The default is "always" that's the safer of the options. It's up to you to
  
• 　　# understand if you can relax this to "everysec" that will fsync every second
  
• 　　# or to "no" that will let the operating system flush the output buffer when
  
• 　　# it want, for better performances (but if you can live with the idea of
  
• 　　# some data loss consider the default persistence mode that's snapshotting).
  
• 
  
• 　　appendfsync always
  
• 　　# appendfsync everysec
  
• 　　# appendfsync no
  
• 
  
• 　　############################### ADVANCED CONFIG ###############################
  
• 
  
• 　　# Glue small output buffers together in order to send small replies in a
  
• 　　# single TCP packet. Uses a bit more CPU but most of the times it is a win
  
• 　　# in terms of number of queries per second. Use 'yes' if unsure.
  
• 　　glueoutputbuf yes
  
• 
  
• 　　# Use object sharing. Can save a lot of memory if you have many common
  
• 　　# string in your dataset, but performs lookups against the shared objects
  
• 　　# pool so it uses more CPU and can be a bit slower. Usually it's a good
  
• 　　# idea.
  
• 　　#
  
• 　　# When object sharing is enabled (shareobjects yes) you can use
  
• 　　# shareobjectspoolsize to control the size of the pool used in order to try
  
• 　　# object sharing. A bigger pool size will lead to better sharing capabilities.
  
• 　　# In general you want this value to be at least the double of the number of
  
• 　　# very common strings you have in your dataset.
  
• 　　#
  
• 　　# WARNING: object sharing is experimental, don't enable this feature
  
• 　　# in production before of Redis 1.0-stable. Still please try this feature in
  
• 　　# your development environment so that we can test it better.
  
• 　　# shareobjects no
  
• 　　# shareobjectspoolsize 1024
  

　　在命令行中进入redis所在目录，输入命令：
　　redis-server.exe redis.conf
　　服务器启动。