一, Redis 配置文件 redis.conf 详解
- # Note on units: when memory size is needed, it is possible to specifiy
- # it in the usual form of 1k 5GB 4M and so forth:
- #
- # 1k => 1000 bytes
- # 1kb => 1024 bytes
- # 1m => 1000000 bytes
- # 1mb => 1024*1024 bytes
- # 1g => 1000000000 bytes
- # 1gb => 1024*1024*1024 bytes
- #
- # units are case insensitive so 1GB 1Gb 1gB are all the same.
- # Redis 默认不是以守护进程的方式运行, 可以通过该配置项修改, 使用 yes 启用守护进程
- # 启用守护进程后, Redis 会把 pid 写到一个 pidfile 中, 在 / var/run/redis.pid
- daemonize no
- # 当 Redis 以守护进程方式运行时, Redis 默认会把 pid 写入 / var/run/redis.pid 文件, 可以通过 pidfile 指定
- pidfile /var/run/redis.pid
- # 指定 Redis 监听端口, 默认端口为 6379
- # 如果指定 0 端口, 表示 Redis 不监听 TCP 连接
- port 6379
- # 绑定的主机地址
- # 你可以绑定单一接口, 如果没有绑定, 所有接口都会监听到来的连接
- # bind 127.0.0.1
- # Specify the path for the unix socket that will be used to listen for
- # incoming connections. There is no default, so Redis will not listen
- # on a unix socket when not specified.
- #
- # unixsocket /tmp/redis.sock
- # unixsocketperm 755
- # 当客户端闲置多长时间后关闭连接, 如果指定为 0, 表示关闭该功能
- timeout 0
- # 指定日志记录级别, Redis 总共支持四个级别: debug,verbose,notice,warning, 默认为 verbose
- # debug (很多信息, 对开发 / 测试比较有用)
- # 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)
- loglevel verbose
- # 日志记录方式, 默认为标准输出, 如果配置为 redis 为守护进程方式运行, 而这里又配置为标准输出, 则日志将会发送给 / dev/null
- logfile stdout
- # 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
- # Specify the syslog identity.
- # syslog-ident redis
- # Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7.
- # syslog-facility local0
- # 设置数据库的数量, 默认数据库为 0, 可以使用 select <dbid > 命令在连接上指定数据库 id
- # dbid 是从 0 到'databases'-1 的数目
- databases 16
- ################################ SNAPSHOTTING #################################
- # 指定在多长时间内, 有多少次更新操作, 就将数据同步到数据文件, 可以多个条件配合
- # Save the DB on disk:
- #
- # save <seconds> <changes>
- #
- # Will save the DB if both the given number of seconds and the given
- # number of write operations against the DB occurred.
- #
- # 满足以下条件将会同步数据:
- # 900 秒 (15 分钟) 内有 1 个更改
- # 300 秒 (5 分钟) 内有 10 个更改
- # 60 秒内有 10000 个更改
- # Note: 可以把所有 "save" 行注释掉, 这样就取消同步操作了
- save 900 1
- save 300 10
- save 60 10000
- # 指定存储至本地数据库时是否压缩数据, 默认为 yes,Redis 采用 LZF 压缩, 如果为了节省 CPU 时间, 可以关闭该选项, 但会导致数据库文件变的巨大
- rdbcompression yes
- # 指定本地数据库文件名, 默认值为 dump.rdb
- dbfilename dump.rdb
- # 工作目录.
- # 指定本地数据库存放目录, 文件名由上一个 dbfilename 配置项指定
- #
- # Also the Append Only File will be created inside this directory.
- #
- # 注意, 这里只能指定一个目录, 不能指定文件名
- dir ./
- ################################# REPLICATION #################################
- # 主从复制. 使用 slaveof 从 Redis 服务器复制一个 Redis 实例. 注意, 该配置仅限于当前 slave 有效
- # 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.
- # 设置当本机为 slav 服务时, 设置 master 服务的 ip 地址及端口, 在 Redis 启动时, 它会自动从 master 进行数据同步
- # slaveof <masterip> <masterport>
- # 当 master 服务设置了密码保护时, slav 服务连接 master 的密码
- # 下文的 "requirepass" 配置项可以指定密码
- # masterauth <master-password>
- # When a slave lost the connection with the master, or when the replication
- # is still in progress, the slave can act in two different ways:
- #
- # 1) if slave-serve-stale-data is set to 'yes' (the default) the slave will
- # still reply to client requests, possibly with out of data data, or the
- # data set may just be empty if this is the first synchronization.
- #
- # 2) if slave-serve-stale data is set to 'no' the slave will reply with
- # an error "SYNC with master in progress" to all the kind of commands
- # but to INFO and SLAVEOF.
- #
- slave-serve-stale-data yes
- # Slaves send PINGs to server in a predefined interval. It's possible to change
- # this interval with the repl_ping_slave_period option. The default value is 10
- # seconds.
- #
- # repl-ping-slave-period 10
- # The following option sets a timeout for both Bulk transfer I/O timeout and
- # master data or ping response timeout. The default value is 60 seconds.
- #
- # It is important to make sure that this value is greater than the value
- # specified for repl-ping-slave-period otherwise a timeout will be detected
- # every time there is low traffic between the master and the slave.
- #
- # repl-timeout 60
- ################################## SECURITY ###################################
- # Warning: since Redis is pretty fast an outside user can try up to
- # 150k passwords per second against a good box. This means that you should
- # use a very strong password otherwise it will be very easy to break.
- # 设置 Redis 连接密码, 如果配置了连接密码, 客户端在连接 Redis 时需要通过 auth <password > 命令提供密码, 默认关闭
- # requirepass foobared
- # Command renaming.
- #
- # It is possilbe to change the name of dangerous commands in a shared
- # environment. For instance the CONFIG command may be renamed into something
- # of hard to guess so that it will be still available for internal-use
- # tools but not available for general clients.
- #
- # Example:
- #
- # rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52
- #
- # It is also possilbe to completely kill a command renaming it into
- # an empty string:
- #
- # rename-command CONFIG ""
- ################################### LIMITS ####################################
- # 设置同一时间最大客户端连接数, 默认无限制, Redis 可以同时打开的客户端连接数为 Redis 进程可以打开的最大文件描述符数,
- # 如果设置 maxclients 0, 表示不作限制. 当客户端连接数到达限制时, Redis 会关闭新的连接并向客户端返回 max Number of clients reached 错误信息
- # 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.
- # 指定 Redis 最大内存限制, Redis 在启动时会把数据加载到内存中, 达到最大内存后, Redis 会先尝试清除已到期或即将到期的 Key,
- # 当此方法处理后, 仍然到达最大内存设置, 将无法再进行写入操作, 但仍然可以进行读取操作.
- # Redis 新的 vm 机制, 会把 Key 存放内存, Value 会存放在 swap 区
- # maxmemory <bytes>
- # MAXMEMORY POLICY: how Redis will select what to remove when maxmemory
- # is reached? You can select among five behavior:
- #
- # volatile-lru -> remove the key with an expire set using an LRU algorithm
- # allkeys-lru -> remove any key accordingly to the LRU algorithm
- # volatile-random -> remove a random key with an expire set
- # allkeys->random -> remove a random key, any key
- # volatile-ttl -> remove the key with the nearest expire time (minor TTL)
- # noeviction -> don't expire at all, just return an error on write operations
- #
- # Note: with all the kind of policies, Redis will return an error on write
- # operations, when there are not suitable keys for eviction.
- #
- # At the date of writing this commands are: set setnx setex append
- # incr decr rpush lpush rpushx lpushx linsert lset rpoplpush sadd
- # sinter sinterstore sunion sunionstore sdiff sdiffstore zadd zincrby
- # zunionstore zinterstore hset hsetnx hmset hincrby incrby decrby
- # getset mset msetnx exec sort
- #
- # The default is:
- #
- # maxmemory-policy volatile-lru
- # LRU and minimal TTL algorithms are not precise algorithms but approximated
- # algorithms (in order to save memory), so you can select as well the sample
- # size to check. For instance for default Redis will check three keys and
- # pick the one that was used less recently, you can change the sample size
- # using the following configuration directive.
- #
- # maxmemory-samples 3
- ############################## APPEND ONLY MODE ###############################
- #
- # 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.
- # 指定是否在每次更新操作后进行日志记录, Redis 在默认情况下是异步的把数据写入磁盘, 如果不开启, 可能会在断电时导致一段时间内的数据丢失.
- # 因为 redis 本身同步数据文件是按上面 save 条件来同步的, 所以有的数据会在一段时间内只存在于内存中. 默认为 no
- # IMPORTANT: Check the BGREWRITEAOF to check how to rewrite the append
- # log file in background when it gets too big.
- appendonly no
- # 指定更新日志文件名, 默认为 appendonly.aof
- # appendfilename appendonly.aof
- # 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.
- # 指定更新日志条件, 共有 3 个可选值:
- # no: 表示等操作系统进行数据缓存同步到磁盘(快)
- # always: 表示每次更新操作后手动调用 fsync()将数据写到磁盘(慢, 安全)
- # everysec: 表示每秒同步一次(折衷, 默认值)
- appendfsync everysec
- # appendfsync no
- # When the AOF fsync policy is set to always or everysec, and a background
- # saving process (a background save or AOF log background rewriting) is
- # performing a lot of I/O against the disk, in some Linux configurations
- # Redis may block too long on the fsync() call. Note that there is no fix for
- # this currently, as even performing fsync in a different thread will block
- # our synchronous write(2) call.
- #
- # In order to mitigate this problem it's possible to use the following option
- # that will prevent fsync() from being called in the main process while a
- # BGSAVE or BGREWRITEAOF is in progress.
- #
- # This means that while another child is saving the durability of Redis is
- # the same as "appendfsync none", that in pratical terms means that it is
- # possible to lost up to 30 seconds of log in the worst scenario (with the
- # default Linux settings).
- #
- # If you have latency problems turn this to "yes". Otherwise leave it as
- # "no" that is the safest pick from the point of view of durability.
- no-appendfsync-on-rewrite no
- # Automatic rewrite of the append only file.
- # Redis is able to automatically rewrite the log file implicitly calling
- # BGREWRITEAOF when the AOF log size will growth by the specified percentage.
- #
- # This is how it works: Redis remembers the size of the AOF file after the
- # latest rewrite (or if no rewrite happened since the restart, the size of
- # the AOF at startup is used).
- #
- # This base size is compared to the current size. If the current size is
- # bigger than the specified percentage, the rewrite is triggered. Also
- # you need to specify a minimal size for the AOF file to be rewritten, this
- # is useful to avoid rewriting the AOF file even if the percentage increase
- # is reached but it is still pretty small.
- #
- # Specify a precentage of zero in order to disable the automatic AOF
- # rewrite feature.
- auto-aof-rewrite-percentage 100
- auto-aof-rewrite-min-size 64mb
- ################################## SLOW LOG ###################################
- # The Redis Slow Log is a system to log queries that exceeded a specified
- # execution time. The execution time does not include the I/O operations
- # like talking with the client, sending the reply and so forth,
- # but just the time needed to actually execute the command (this is the only
- # stage of command execution where the thread is blocked and can not serve
- # other requests in the meantime).
- #
- # You can configure the slow log with two parameters: one tells Redis
- # what is the execution time, in microseconds, to exceed in order for the
- # command to get logged, and the other parameter is the length of the
- # slow log. When a new command is logged the oldest one is removed from the
- # queue of logged commands.
- # The following time is expressed in microseconds, so 1000000 is equivalent
- # to one second. Note that a negative number disables the slow log, while
- # a value of zero forces the logging of every command.
- slowlog-log-slower-than 10000
- # There is no limit to this length. Just be aware that it will consume memory.
- # You can reclaim memory used by the slow log with SLOWLOG RESET.
- slowlog-max-len 1024
- ################################ VIRTUAL MEMORY ###############################
- ### WARNING! Virtual Memory is deprecated in Redis 2.4
- ### The use of Virtual Memory is strongly discouraged.
- ### WARNING! Virtual Memory is deprecated in Redis 2.4
- ### The use of Virtual Memory is strongly discouraged.
- # Virtual Memory allows Redis to work with datasets bigger than the actual
- # amount of RAM needed to hold the whole dataset in memory.
- # In order to do so very used keys are taken in memory while the other keys
- # are swapped into a swap file, similarly to what operating systems do
- # with memory pages.
- # 指定是否启用虚拟内存机制, 默认值为 no,
- # VM 机制将数据分页存放, 由 Redis 将访问量较少的页即冷数据 swap 到磁盘上, 访问多的页面由磁盘自动换出到内存中
- # 把 vm-enabled 设置为 yes, 根据需要设置好接下来的三个 VM 参数, 就可以启动 VM 了
- vm-enabled no
- # vm-enabled yes
- # This is the path of the Redis swap file. As you can guess, swap files
- # can't be shared by different Redis instances, so make sure to use a swap
- # file for every redis process you are running. Redis will complain if the
- # swap file is already in use.
- #
- # Redis 交换文件最好的存储是 SSD(固态硬盘)
- # 虚拟内存文件路径, 默认值为 / tmp/redis.swap, 不可多个 Redis 实例共享
- # *** WARNING *** if you are using a shared hosting the default of putting
- # the swap file under /tmp is not secure. Create a dir with access granted
- # only to Redis user and configure Redis to create the swap file there.
- vm-swap-file /tmp/redis.swap
- # With vm-max-memory 0 the system will swap everything it can. Not a good
- # default, just specify the max amount of RAM you can in bytes, but it's
- # better to leave some margin. For instance specify an amount of RAM
- # that's more or less between 60 and 80% of your free RAM.
- # 将所有大于 vm-max-memory 的数据存入虚拟内存, 无论 vm-max-memory 设置多少, 所有索引数据都是内存存储的(Redis 的索引数据就是 keys)
- # 也就是说当 vm-max-memory 设置为 0 的时候, 其实是所有 value 都存在于磁盘. 默认值为 0
- vm-max-memory 0
- # Redis swap 文件分成了很多的 page, 一个对象可以保存在多个 page 上面, 但一个 page 上不能被多个对象共享, vm-page-size 是要根据存储的数据大小来设定的.
- # 建议如果存储很多小对象, page 大小最后设置为 32 或 64bytes; 如果存储很大的对象, 则可以使用更大的 page, 如果不确定, 就使用默认值
- vm-page-size 32
- # 设置 swap 文件中的 page 数量由于页表 (一种表示页面空闲或使用的 bitmap) 是存放在内存中的, 在磁盘上每 8 个 pages 将消耗 1byte 的内存
- # swap 空间总容量为 vm-page-size * vm-pages
- #
- # With the default of 32-bytes memory pages and 134217728 pages Redis will
- # use a 4 GB swap file, that will use 16 MB of RAM for the page table.
- #
- # It's better to use the smallest acceptable value for your application,
- # but the default is large in order to work in most conditions.
- vm-pages 134217728
- # Max number of VM I/O threads running at the same time.
- # This threads are used to read/write data from/to swap file, since they
- # also encode and decode objects from disk to memory or the reverse, a bigger
- # number of threads can help with big objects even if they can't help with
- # I/O itself as the physical device may not be able to couple with many
- # reads/writes operations at the same time.
- # 设置访问 swap 文件的 I/O 线程数, 最后不要超过机器的核数, 如果设置为 0, 那么所有对 swap 文件的操作都是串行的, 可能会造成比较长时间的延迟, 默认值为 4
- vm-max-threads 4
- ############################### ADVANCED CONFIG ###############################
- # Hashes are encoded in a special way (much more memory efficient) when they
- # have at max a given numer of elements, and the biggest element does not
- # exceed a given threshold. You can configure this limits with the following
- # configuration directives.
- # 指定在超过一定的数量或者最大的元素超过某一临界值时, 采用一种特殊的哈希算法
- hash-max-zipmap-entries 512
- hash-max-zipmap-value 64
- # Similarly to hashes, small lists are also encoded in a special way in order
- # to save a lot of space. The special representation is only used when
- # you are under the following limits:
- list-max-ziplist-entries 512
- list-max-ziplist-value 64
- # Sets have a special encoding in just one case: when a set is composed
- # of just strings that happens to be integers in radix 10 in the range
- # of 64 bit signed integers.
- # The following configuration setting sets the limit in the size of the
- # set in order to use this special memory saving encoding.
- set-max-intset-entries 512
- # Similarly to hashes and lists, sorted sets are also specially encoded in
- # order to save a lot of space. This encoding is only used when the length and
- # elements of a sorted set are below the following limits:
- zset-max-ziplist-entries 128
- zset-max-ziplist-value 64
- # Active rehashing uses 1 millisecond every 100 milliseconds of CPU time in
- # order to help rehashing the main Redis hash table (the one mapping top-level
- # keys to values). The hash table implementation redis uses (see dict.c)
- # performs a lazy rehashing: the more operation you run into an hash table
- # that is rhashing, the more rehashing "steps" are performed, so if the
- # server is idle the rehashing is never complete and some more memory is used
- # by the hash table.
- #
- # The default is to use this millisecond 10 times every second in order to
- # active rehashing the main dictionaries, freeing memory when possible.
- #
- # If unsure:
- # use "activerehashing no" if you have hard latency requirements and it is
- # not a good thing in your environment that Redis can reply form time to time
- # to queries with 2 milliseconds delay.
- # 指定是否激活重置哈希, 默认为开启
- activerehashing yes
- ################################## INCLUDES ###################################
- # 指定包含其他的配置文件, 可以在同一主机上多个 Redis 实例之间使用同一份配置文件, 而同时各实例又拥有自己的特定配置文件
- # include /path/to/local.conf
- # include /path/to/other.conf
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