102.【Redis】(八)

本文涉及的产品
Redis 开源版,标准版 2GB
推荐场景:
搭建游戏排行榜
云数据库 Tair(兼容Redis),内存型 2GB
简介: 102.【Redis】

(十)、Redis.config

  • redis在启动的时候,就通过配置文件来启动!
  • 工作中,一些小小的配置,可以让你脱颖而出!

1.容量单位

配置文件 unit单位 对大小写不敏感!

# Note on units: when memory size is needed, it is possible to specify
# it in the usual form of 1k 5GB 4M and so forth:
单位
# 1k => 1000 bytes
# 1kb => 1024 bytes
# 1m => 1000000 bytes
# 1mb => 1024*1024 bytes
# 1g => 1000000000 bytes
# 1gb => 1024*1024*1024 bytes
对大小写不敏感
# units are case insensitive so 1GB 1Gb 1gB are all the same.

2.包含

就相当于import,可以把其他的配置文件配置过来

################################## INCLUDES ###################################
# Include one or more other config files here.  This is useful if you
# have a standard template that goes to all Redis servers but also need
# to customize a few per-server settings.  Include files can include
# other files, so use this wisely.
#
# Note that option "include" won't be rewritten by command "CONFIG REWRITE"
# from admin or Redis Sentinel. Since Redis always uses the last processed
# line as value of a configuration directive, you'd better put includes
# at the beginning of this file to avoid overwriting config change at runtime.
#
# If instead you are interested in using includes to override configuration
# options, it is better to use include as the last line.
#
# Included paths may contain wildcards. All files matching the wildcards will
# be included in alphabetical order.
# Note that if an include path contains a wildcards but no files match it when
# the server is started, the include statement will be ignored and no error will
# be emitted.  It is safe, therefore, to include wildcard files from empty
# directories.
可以引入配置
# include /path/to/local.conf
# include /path/to/other.conf
# include /path/to/fragments/*.conf

3.文件

################################## MODULES #####################################
# Load modules at startup. If the server is not able to load modules
# it will abort. It is possible to use multiple loadmodule directives.
加载一些so文件
# loadmodule /path/to/my_module.so
# loadmodule /path/to/other_module.so

4.网络

################################## NETWORK #####################################
# By default, if no "bind" configuration directive is specified, Redis listens
# for connections from all available network interfaces on the host machine.
# It is possible to listen to just one or multiple selected interfaces using
# the "bind" configuration directive, followed by one or more IP addresses.
# Each address can be prefixed by "-", which means that redis will not fail to
# start if the address is not available. Being not available only refers to
# addresses that does not correspond to any network interface. Addresses that
# are already in use will always fail, and unsupported protocols will always BE
# silently skipped.
#
# Examples:
#
# bind 192.168.1.100 10.0.0.1     # listens on two specific IPv4 addresses
# bind 127.0.0.1 ::1              # listens on loopback IPv4 and IPv6
# bind * -::*                     # like the default, all available interfaces
#
# ~~~ WARNING ~~~ If the computer running Redis is directly exposed to the
# internet, binding to all the interfaces is dangerous and will expose the
# instance to everybody on the internet. So by default we uncomment the
# following bind directive, that will force Redis to listen only on the
# IPv4 and IPv6 (if available) loopback interface addresses (this means Redis
# will only be able to accept client connections from the same host that it is
# running on).
#
# IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES
# COMMENT OUT THE FOLLOWING LINE.
#
# You will also need to set a password unless you explicitly disable protected
# mode.
如果我们需要允许远程访问,我们需要把bind 给注释掉
bind 127.0.0.1 -::1
# By default, outgoing connections (from replica to master, from Sentinel to
# instances, cluster bus, etc.) are not bound to a specific local address. In
# most cases, this means the operating system will handle that based on routing
# and the interface through which the connection goes out.
#
# Using bind-source-addr it is possible to configure a specific address to bind
# to, which may also affect how the connection gets routed.
# Example:
#
# bind-source-addr 10.0.0.1
# Protected mode is a layer of security protection, in order to avoid that
# Redis instances left open on the internet are accessed and exploited.
#
# When protected mode is on and the default user has no password, the server
# only accepts local connections from the IPv4 address (127.0.0.1), IPv6 address
# (::1) or Unix domain sockets.
#
# By default protected mode is enabled. You should disable it only if
# you are sure you want clients from other hosts to connect to Redis
# even if no authentication is configured.
保护模式: 假如我们需要远程就设置no ,本地就yes
protected-mode no
# no    - Block for any connection (remain immutable)
# yes   - Allow for any connection (no protection)
# local - Allow only for local connections. Ones originating from the
#         IPv4 address (127.0.0.1), IPv6 address (::1) or Unix domain sockets.
#
# enable-protected-configs no
# enable-debug-command no
# enable-module-command no
# Accept connections on the specified port, default is 6379 (IANA #815344).
# If port 0 is specified Redis will not listen on a TCP socket.
端口号:
port 5555

5.通用

################################# GENERAL #####################################
# 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.
# When Redis is supervised by upstart or systemd, this parameter has no impact.
保护进程: 默认是no ,我们需要开启yes
daemonize yes
# If you run Redis from upstart or systemd, Redis can interact with your
# supervision tree. Options:
#   supervised no      - no supervision interaction
#   supervised upstart - signal upstart by putting Redis into SIGSTOP mode
#                        requires "expect stop" in your upstart job config
#   supervised systemd - signal systemd by writing READY=1 to $NOTIFY_SOCKET
#                        on startup, and updating Redis status on a regular
#                        basis.
#   supervised auto    - detect upstart or systemd method based on
#                        UPSTART_JOB or NOTIFY_SOCKET environment variables
# Note: these supervision methods only signal "process is ready."
#       They do not enable continuous pings back to your supervisor.
#
# The default is "no". To run under upstart/systemd, you can simply uncomment
# the line below:
# If you run Redis from upstart or systemd, Redis can interact with your
# supervision tree. Options:
#   supervised no      - no supervision interaction
#   supervised upstart - signal upstart by putting Redis into SIGSTOP mode
#                        requires "expect stop" in your upstart job config
#   supervised systemd - signal systemd by writing READY=1 to $NOTIFY_SOCKET
#                        on startup, and updating Redis status on a regular
#                        basis.
#   supervised auto    - detect upstart or systemd method based on
#                        UPSTART_JOB or NOTIFY_SOCKET environment variables
# Note: these supervision methods only signal "process is ready."
#       They do not enable continuous pings back to your supervisor.
#
# The default is "no". To run under upstart/systemd, you can simply uncomment
# the line below:
管理守护进程的,默认为no.我们不用管
# supervised auto
# If a pid file is specified, Redis writes it where specified at startup
# and removes it at exit.
#
# When the server runs non daemonized, no pid file is created if none is
# specified in the configuration. When the server is daemonized, the pid file
# is used even if not specified, defaulting to "/var/run/redis.pid".
#
# Creating a pid file is best effort: if Redis is not able to create it
# nothing bad happens, the server will start and run normally.
#
# Note that on modern Linux systems "/run/redis.pid" is more conforming
# and should be used instead.
如果以后台的方式运行,我们就需要指定一个pid --进程文件
pidfile /var/run/redis_6379.pid
# Specify the server verbosity level.
# This can be one of:
# debug (a lot of information, useful for development/testing)
# verbose (many rarely useful info, but not a mess like the debug level)
# notice (moderately verbose, what you want in production probably)
# warning (only very important / critical messages are logged)
日志级别: debug测试和开发 (一般不用配置)
loglevel notice
# Specify the log file name. Also the empty string can be used to force
# Redis to log on the standard output. Note that if you use standard
# output for logging but daemonize, logs will be sent to /dev/null
日志生成的文件位置,如果为null,那么就是控制台输出
logfile ""
# To enable logging to the system logger, just set 'syslog-enabled' to yes,
# and optionally update the other syslog parameters to suit your needs.
# syslog-enabled no
# Set the number of databases. The default database is DB 0, you can select
# a different one on a per-connection basis using SELECT <dbid> where
# dbid is a number between 0 and 'databases'-1
默认有16个数据库
databases 16
# However it is possible to force the pre-4.0 behavior and always show a
# ASCII art logo in startup logs by setting the following option to yes.
是否显示Redis的log
always-show-logo no
# By default, Redis modifies the process title (as seen in 'top' and 'ps') to
# provide some runtime information. It is possible to disable this and leave
# the process name as executed by setting the following to no.

6.快照

持久化,在规定的时间内执行了多少次操作,则会持久化到文件 .rdb .aof

Redis是内存数据库,如果没有持久化,那么数据就会断电就失去

################################ SNAPSHOTTING  ################################
# Save the DB to disk.
#
# save <seconds> <changes> [<seconds> <changes> ...]
#
# Redis will save the DB if the given number of seconds elapsed and it
# surpassed the given number of write operations against the DB.
#
# Snapshotting can be completely disabled with a single empty string argument
# as in following example:
#
# save ""
#
# Unless specified otherwise, by default Redis will save the DB:
#   * After 3600 seconds (an hour) if at least 1 change was performed
#   * After 300 seconds (5 minutes) if at least 100 changes were performed
#   * After 60 seconds if at least 10000 changes were performed
#
# You can set these explicitly by uncommenting the following line.
如果 3600秒内,如果至少有一个key进行了修改。那么我们就进行持久化操作
如果在300秒内,至少有100个key进行了修改。那么我们就进行持久化操作
如果在60秒内,有10000个key进行了修改。那么我们就进行持久化操作
# save 3600 1 300 100 60 10000
# If the background saving process will start working again Redis will
# automatically allow writes again.
#
# However if you have setup your proper monitoring of the Redis server
# and persistence, you may want to disable this feature so that Redis will
# continue to work as usual even if there are problems with disk,
# permissions, and so forth.
持久化如果出错,是否还需要继续工作
stop-writes-on-bgsave-error yes
# Compress string objects using LZF when dump .rdb databases?
# By default compression is enabled 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.
是否压缩rdb文件,如果yes会消耗cpu
rdbcompression yes
# RDB files created with checksum disabled have a checksum of zero that will
# tell the loading code to skip the check.
保存rdb文件的时候,是否进行检查校验
rdbchecksum yes
# Enables or disables full sanitization checks for ziplist and listpack etc when
# loading an RDB or RESTORE payload. This reduces the chances of a assertion or
# crash later on while processing commands.
# Options:
#   no         - Never perform full sanitization
#   yes        - Always perform full sanitization
#   clients    - Perform full sanitization only for user connections.
#                Excludes: RDB files, RESTORE commands received from the master
#                connection, and client connections which have the
#                skip-sanitize-payload ACL flag.
# The default should be 'clients' but since it currently affects cluster
# resharding via MIGRATE, it is temporarily set to 'no' by default.
#
# sanitize-dump-payload no
# The filename where to dump the DB
dbfilename dump.rdb
# Remove RDB files used by replication in instances without persistence
# enabled. By default this option is disabled, however there are environments
# where for regulations or other security concerns, RDB files persisted on
# disk by masters in order to feed replicas, or stored on disk by replicas
# in order to load them for the initial synchronization, should be deleted
# ASAP. Note that this option ONLY WORKS in instances that have both AOF
# and RDB persistence disabled, otherwise is completely ignored.
#
# An alternative (and sometimes better) way to obtain the same effect is
# to use diskless replication on both master and replicas instances. However
# in the case of replicas, diskless is not always an option.
rdb-del-sync-files no
# The working directory.
#
# The DB will be written inside this directory, with the filename specified
# above using the 'dbfilename' configuration directive.
#
# The Append Only File will also be created inside this directory.
#
# Note that you must specify a directory here, not a file name.
文件保存的目录
dir ./

7.主从复制

# 2) If replica-serve-stale-data is set to 'no' the replica will reply with error
#    "MASTERDOWN Link with MASTER is down and replica-serve-stale-data is set to 'no'"
#    to all data access commands, excluding commands such as:
#    INFO, REPLICAOF, AUTH, SHUTDOWN, REPLCONF, ROLE, CONFIG, SUBSCRIBE,
#    UNSUBSCRIBE, PSUBSCRIBE, PUNSUBSCRIBE, PUBLISH, PUBSUB, COMMAND, POST,
#    HOST and LATENCY.
#
是否只保存一些数据
replica-serve-stale-data yes
# You can configure a replica instance to accept writes or not. Writing against
# a replica instance may be useful to store some ephemeral data (because data
# written on a replica will be easily deleted after resync with the master) but
# may also cause problems if clients are writing to it because of a
# misconfiguration.
#
# Since Redis 2.6 by default replicas are read-only.
#
# Note: read only replicas are not designed to be exposed to untrusted clients
# on the internet. It's just a protection layer against misuse of the instance.
# Still a read only replica exports by default all the administrative commands
# such as CONFIG, DEBUG, and so forth. To a limited extent you can improve
# security of read only replicas using 'rename-command' to shadow all the
# administrative / dangerous commands.
是否只读
replica-read-only yes

8.安全

acllog-max-len 128
# Using an external ACL file
#
# Instead of configuring users here in this file, it is possible to use
# a stand-alone file just listing users. The two methods cannot be mixed:
# if you configure users here and at the same time you activate the external
# ACL file, the server will refuse to start.
#
# The format of the external ACL user file is exactly the same as the
# format that is used inside redis.conf to describe users.
#
# aclfile /etc/redis/users.acl
# IMPORTANT NOTE: starting with Redis 6 "requirepass" is just a compatibility
# layer on top of the new ACL system. The option effect will be just setting
# the password for the default user. Clients will still authenticate using
# AUTH <password> as usually, or more explicitly with AUTH default <password>
# if they follow the new protocol: both will work.
#
# The requirepass is not compatible with aclfile option and the ACL LOAD
# command, these will cause requirepass to be ignored.
#
在这里设置密码
requirepass ******

9.客户端

################################### CLIENTS ####################################
# Set the max number of connected clients at the same time. By default
# this limit is set to 10000 clients, however if the Redis server is not
# able to configure the process file limit to allow for the specified limit
# the max number of allowed clients is set to the current file limit
# minus 32 (as Redis reserves a few file descriptors for internal uses).
#
# Once the limit is reached Redis will close all the new connections sending
# an error 'max number of clients reached'.
#
# IMPORTANT: When Redis Cluster is used, the max number of connections is also
# shared with the cluster bus: every node in the cluster will use two
# connections, one incoming and another outgoing. It is important to size the
# limit accordingly in case of very large clusters.
设置redis最大连接服务端的数量为1000
# maxclients 10000
############################## MEMORY MANAGEMENT ################################
# Set a memory usage limit to the specified amount of bytes.
# When the memory limit is reached Redis will try to remove keys
# according to the eviction policy selected (see maxmemory-policy).
#
# If Redis can't remove keys according to the policy, or if the policy is
# set to 'noeviction', Redis will start to reply with errors to commands
# that would use more memory, like SET, LPUSH, and so on, and will continue
# to reply to read-only commands like GET.
#
# This option is usually useful when using Redis as an LRU or LFU cache, or to
# set a hard memory limit for an instance (using the 'noeviction' policy).
#
# WARNING: If you have replicas attached to an instance with maxmemory on,
# the size of the output buffers needed to feed the replicas are subtracted
# from the used memory count, so that network problems / resyncs will
# not trigger a loop where keys are evicted, and in turn the output
# buffer of replicas is full with DELs of keys evicted triggering the deletion
# of more keys, and so forth until the database is completely emptied.
#
# In short... if you have replicas attached it is suggested that you set a lower
# limit for maxmemory so that there is some free RAM on the system for replica
# output buffers (but this is not needed if the policy is 'noeviction').
Redis 配置的最大内存容量
# maxmemory <bytes>
# Note: with any of the above policies, when there are no suitable keys for
# eviction, Redis will return an error on write operations that require
# more memory. These are usually commands that create new keys, add data or
# modify existing keys. A few examples are: SET, INCR, HSET, LPUSH, SUNIONSTORE,
# SORT (due to the STORE argument), and EXEC (if the transaction includes any
# command that requires memory).
#
# The default is:
内存达到上限之后的策略
# maxmemory-policy noeviction

10.aof配置

############################## APPEND ONLY MODE ###############################
# By default Redis asynchronously dumps the dataset on disk. This mode is
# good enough in many applications, but an issue with the Redis process or
# a power outage may result into a few minutes of writes lost (depending on
# the configured save points).
#
# The Append Only File is an alternative persistence mode that provides
# much better durability. For instance using the default data fsync policy
# (see later in the config file) Redis can lose just one second of writes in a
# dramatic event like a server power outage, or a single write if something
# wrong with the Redis process itself happens, but the operating system is
# still running correctly.
#
# AOF and RDB persistence can be enabled at the same time without problems.
# If the AOF is enabled on startup Redis will load the AOF, that is the file
# with the better durability guarantees.
#
# Please check https://redis.io/topics/persistence for more information.
默认aof不开启,默认使用rdb进行持久化的
appendonly no
# - appendonly.aof.1.base.rdb as a base file.
# - appendonly.aof.1.incr.aof, appendonly.aof.2.incr.aof as incremental files.
# - appendonly.aof.manifest as a manifest file.
持久化文件的饿名字
appendfilename "appendonly.aof"
# For convenience, Redis stores all persistent append-only files in a dedicated
# directory. The name of the directory is determined by the appenddirname
# configuration parameter.
持久化文件目录的名字
appenddirname "appendonlydir"
每次修改都会同步
# appendfsync always
每秒执行一次同步,但可能会丢失这一秒的数据
appendfsync everysec
每次修改都不会同步
# appendfsync no

(十一)、Redis持久化

Redis 是内存数据库,如果不将内存中的数据库状态保存到磁盘,那么一旦服务器进程退出,服务器中的数据库状态也会消失。所以 Redis 提供了持久化的功能

1.RDB

什么是RDB

工作原理:

fork()函数用于从一个已经存在的进程内创建一个新的进程,称为“子进程”。

在指定的时间间隔内将内存中的数据集快照写入磁盘,也就是行话讲的Snapshot快照,它恢复时是将快照文件直接读到内存里

Redis会单独创建(fork)一个子进程来进行持久化,会先将数据写入到一个临时文件中,待持久化过程都结束了,再用这个临时文件替换上次持久化好的文件。整个过程中,主进程是不进行任何IO操作的。

这就确保了极高的性能。如果需要进行大规模数据的恢复,且对于数据恢复的完整性不是非常敏感,那RDB方式要比AOF方式更加的高效。RDB的缺点是最后一次持久化后的数据可能丢失。我们默认的就是RDB,一般情况下不需要修改这个配置!

有时候在生产环境我们会对这个文件进行备份!

rdb保存的文件默认是dump.rdb,都是在我们的配置文件中进行配置的,一般不需要改动!

vim 搜索

/ 搜索的内容  然后回车

触发机制:

  • save的规则满足的情况下,会自动触发rdb规则
  • 执行 flushall 命令,也会触发我们的rdb规则!
  • 退出redis,也会产生 rdb 文件!
  • 备份就自动生成一个 dump.rdb

如何恢复rdb文件

只需要将rdb文件放在我们的redis启动目录下就可以redis在启动时就会自动检查dump.rdb并恢复其中的数据

查看 dump.rdb 需要存放的位置 。

config get dir

优点:

  • 适合大规模的数据恢复!
  • 对数据的完整性要不高!

缺点:

  • 需要一定的时间间隔进行操作!如果redis意外宕机了,这个最后一次修改数据就没有了!
  • fork进程的时候,会占用一定的内存空间。

相关实践学习
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云数据库Redis版是兼容Redis协议标准的、提供持久化的内存数据库服务,基于高可靠双机热备架构及可无缝扩展的集群架构,满足高读写性能场景及容量需弹性变配的业务需求。 产品详情:https://www.aliyun.com/product/kvstore &nbsp; &nbsp; ------------------------------------------------------------------------- 阿里云数据库体验:数据库上云实战 开发者云会免费提供一台带自建MySQL的源数据库&nbsp;ECS 实例和一台目标数据库&nbsp;RDS实例。跟着指引,您可以一步步实现将ECS自建数据库迁移到目标数据库RDS。 点击下方链接,领取免费ECS&amp;RDS资源,30分钟完成数据库上云实战!https://developer.aliyun.com/adc/scenario/51eefbd1894e42f6bb9acacadd3f9121?spm=a2c6h.13788135.J_3257954370.9.4ba85f24utseFl
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