redis.conf配置文件详细讲解(二)

ABKYH

　　4.      常用配置说明
　　####GENERAL #####################################[l1]
　　# Bydefault Redis does not run as a daemon. Use 'yes' if you need it.
　　# Note that Redis will write a pid filein /var/run/redis.pid when daemonized.[l2]
　　daemonize no
　　#If you run Redis from upstart or systemd, Redis can interact with your
　　# supervision tree. Options:[l3]
　　#   supervised no      - no supervision interaction[l4]
　　#   supervised upstart - signal upstartby putting Redis into SIGSTOP mode[l5]
　　#   supervised systemd - signal systemdby writing READY=1 to $NOTIFY_SOCKET[l6]
　　#   supervised auto    - detect upstart or systemd method based on
　　#                        UPSTART_JOB orNOTIFY_SOCKET environment variables[l7]
　　#Note: these supervision methods only signal "process is ready."[l8]
　　#       They do not enable continuous livenesspings back to your supervisor.[l9]
　　supervised no
　　#If a pid file is specified, Redis writes it where specified at startup
　　# and removes it at exit.[l10]
　　#
　　# Whenthe server runs non daemonized, no pid file is created if none is
　　# specified in the configuration. Whenthe server is daemonized, the pid file
　　# is used even if not specified,defaulting to "/var/run/redis.pid".[l11]
　　#
　　#Creating a pid file is best effort: if Redis is not able to create it
　　# nothing bad happens, the server willstart and run normally.[l12]
　　pidfile /var/run/redis_6379.pid
　　# Specifythe server verbosity level.[l13]
　　# Thiscan be one of:
　　# debug (a lot of information, useful fordevelopment/testing)
　　# verbose (many rarely useful info, butnot a mess like the debug level)
　　# notice (moderately verbose, what youwant in production probably)
　　# warning (only very important / criticalmessages are logged)[l14]
　　loglevel notice
　　# Specifythe 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, logswill be sent to /dev/null[l15]
　　logfile ""
　　# Toenable logging to the system logger, just set 'syslog-enabled' to yes,
　　# and optionally update the other syslogparameters to suit your needs.
　　# syslog-enabled no[l16]

　　# Specifythe syslog>　　# syslog-ident redis
　　# Specifythe syslog facility. Must be USER or between LOCAL0-LOCAL7.[l18]
　　# syslog-facility local0
　　# Setthe number of databases. The default database is DB 0, you can select
　　# a different one on a per-connectionbasis using SELECT  where
　　# dbid is a number between 0 and'databases'-1[l19]
　　databases 16
　　5.      快照设置说明
　　###### SNAPSHOTTING[l20]   ################################
　　#
　　#Save the DB on disk:[l21]
　　#
　　#   save  [l22]
　　#
　　#   Will save the DB if both the given numberof seconds and the given
　　#  number of write operations against the DB occurred.[l23]
　　#
　　#   In the example below the behaviour will beto 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[l24]
　　#
　　#   Note: you can disable saving completely bycommenting out all "save" lines.[l25]
　　#
　　#   It is also possible to remove all thepreviously configured save
　　#  points by adding a save directive with a single empty string argument
　　#  like in the following example:
　　#
　　#  save ""[l26]
　　save 900 1
　　save 300 10
　　save 60 10000
　　# Bydefault Redis will stop accepting writes if RDB snapshots are enabled
　　# (at least one save point) and thelatest background save failed.
　　# This will make the user aware (in ahard way) that data is not persisting
　　# on disk properly, otherwise chances arethat no one will notice and some
　　# disaster will happen.[l27]
　　#
　　# Ifthe background saving process will start working again Redis will
　　# automatically allow writes again.[l28]
　　#
　　# Howeverif you have setup your proper monitoring of the Redis server
　　# and persistence, you may want todisable this feature so that Redis will
　　# continue to work as usual even if thereare problems with disk,
　　# permissions, and so forth.[l29]
　　stop-writes-on-bgsave-error yes
　　#Compress string objects using LZF when dump .rdb databases?
　　# For default that's set to 'yes' as it'salmost always a win.
　　# If you want to save some CPU in thesaving child set it to 'no' but
　　# the dataset will likely be bigger ifyou have compressible values or keys.[l30]
　　rdbcompression yes
　　#Since version 5 of RDB a CRC64 checksum is placed at the end of the file.
　　# This makes the format more resistant tocorruption but there is a performance
　　# hit to pay (around 10%) when saving andloading RDB files, so you can disable it
　　# for maximum performances.[l31]
　　#
　　#RDB files created with checksum disabled have a checksum of zero that will
　　# tell the loading code to skip thecheck.[l32]
　　rdbchecksum yes
　　# Thefilename where to dump the DB[l33]
　　dbfilename dump.rdb
　　# Theworking directory.[l34]
　　#
　　# TheDB will be written inside this directory, with the filename specified
　　# above using the 'dbfilename'configuration directive.[l35]
　　#
　　# TheAppend Only File will also be created inside this directory.[l36]
　　#
　　# Notethat you must specify a directory here, not a file name.[l37]
　　dir ./
　　6.      主从复制设置说明
　　######## REPLICATION[l38] #################################
　　# Master-Slavereplication. Use slaveof to make a Redis instance a copy of
　　# another Redis server. A few things tounderstand ASAP about Redis replication.[l39]
　　#
　　# 1)Redis replication is asynchronous, but you can configure a master to
　　#   stop accepting writes if it appears to be not connected with at least
　　#   a given number of slaves.[l40]
　　#2) Redis slaves are able to perform a partial resynchronization with the

　　#   master if the replication link is lost for a>
　　#   time. You may want to configure the replication backlog>　　#   sections of this file) with a sensible value depending on your needs.[l41]
　　#3) Replication is automatic and does not need user intervention. After a
　　#   network partition slaves automatically try to reconnect to masters
　　#   and resynchronize with them.[l42]
　　#
　　#slaveof  [l43]
　　#If the master is password protected (using the "requirepass"configuration
　　# directive below) it is possible to tellthe slave to authenticate before
　　# starting the replicationsynchronization process, otherwise the master will
　　# refuse the slave request.[l44]
　　#
　　# masterauth
　　# Whena slave loses its connection with the master, or when the replication
　　# is still in progress, the slave can actin two different ways:[l45]
　　#
　　# 1)if slave-serve-stale-data is set to 'yes' (the default) the slave will
　　#   still reply to client requests, possibly with out of date data, or the
　　#   data set may just be empty if this is the first synchronization.[l46]
　　#
　　#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 ofcommands
　　#   but to INFO and SLAVEOF.[l47]
　　#
　　slave-serve-stale-data yes
　　# Youcan configure a slave instance to accept writes or not. Writing against
　　# a slave instance may be useful to storesome ephemeral data (because data
　　# written on a slave will be easilydeleted after resync with the master) but
　　# may also cause problems if clients arewriting to it because of a
　　# misconfiguration.[l48]
　　#
　　#Since Redis 2.6 by default slaves are read-only[l49] .
　　#
　　# Note:read only slaves are not designed to be exposed to untrusted clients
　　# on the internet. It's just a protectionlayer against misuse of the instance.
　　# Still a read only slave exports bydefault all the administrative commands
　　# such as CONFIG, DEBUG, and so forth. Toa limited extent you can improve
　　# security of read only slaves using'rename-command' to shadow all the
　　# administrative / dangerous commands.[l50]
　　slave-read-only yes
　　#Replication SYNC strategy: disk or socket.[l51]
　　#
　　# -------------------------------------------------------
　　#WARNING: DISKLESS REPLICATION IS EXPERIMENTAL CURRENTLY[l52]
　　# -------------------------------------------------------
　　#
　　# Newslaves and reconnecting slaves that are not able to continue the replication
　　# process just receiving differences,need to do what is called a "full
　　# synchronization". An RDB file istransmitted from the master to the slaves.
　　# The transmission can happen in twodifferent ways:[l53]
　　#
　　# 1)Disk-backed: The Redis master creates a new process that writes the RDB
　　#                 file on disk. Later the fileis transferred by the parent
　　#                 process to the slavesincrementally.[l54]
　　#2) Diskless: The Redis master creates a new process that directly writes the
　　#             RDB file to slave sockets,without touching the disk at all.[l55]
　　#
　　# Withdisk-backed replication, while the RDB file is generated, more slaves
　　# can be queued and served with the RDBfile as soon as the current child producing
　　# the RDB file finishes its work. Withdiskless replication instead once
　　# the transfer starts, new slavesarriving will be queued and a new transfer
　　# will start when the current oneterminates.[l56]
　　#
　　#When diskless replication is used, the master waits a configurable amount of
　　# time (in seconds) before starting thetransfer in the hope that multiple slaves
　　# will arrive and the transfer can beparallelized.[l57]
　　#
　　# Withslow disks and fast (large bandwidth) networks, diskless replication
　　# works better.[l58]
　　repl-diskless-sync no
　　# Whendiskless replication is enabled, it is possible to configure the delay
　　# the server waits in order to spawn thechild that transfers the RDB via socket
　　# to the slaves[l59] .
　　#
　　# Thisis important since once the transfer starts, it is not possible to serve
　　# new slaves arriving, that will bequeued for the next RDB transfer, so the server
　　# waits a delay in order to let moreslaves arrive.[l60]
　　#
　　# Thedelay is specified in seconds, and by default is 5 seconds. To disable
　　# it entirely just set it to 0 secondsand the transfer will start ASAP.[l61]
　　repl-diskless-sync-delay 5
　　# Slavessend PINGs to server in a predefined interval. It's possible to change
　　# this interval with the repl_ping_slave_periodoption. The default value is 10
　　# seconds.[l62]
　　#
　　# repl-ping-slave-period 10
　　# Thefollowing option sets the replication timeout for:[l63]
　　#
　　# 1)Bulk transfer I/O during SYNC, from the point of view of slave.
　　# 2) Master timeout from the point ofview of slaves (data, pings).
　　# 3) Slave timeout from the point of viewof masters (REPLCONF ACK pings).[l64]
　　#
　　#It is important to make sure that this value is greater than the value
　　# specified for repl-ping-slave-periodotherwise a timeout will be detected
　　# every time there is low traffic betweenthe master and the slave.[l65]
　　#
　　# repl-timeout 60
　　# DisableTCP_NODELAY on the slave socket after SYNC?[l66]
　　#
　　#If you select "yes" Redis will use a smaller number of TCP packetsand
　　# less bandwidth to send data to slaves.But this can add a delay for
　　# the data to appear on the slave side,up to 40 milliseconds with
　　# Linux kernels using a defaultconfiguration.[l67]
　　#
　　# Ifyou select "no" the delay for data to appear on the slave side will
　　# be reduced but more bandwidth will beused for replication.[l68]
　　#
　　#By default we optimize for low latency, but in very high traffic conditions
　　# or when the master and slaves are manyhops away, turning this to "yes" may

　　# be a good>　　repl-disable-tcp-nodelay no

　　#Set the replication backlog>　　# slave data when slaves are disconnectedfor some time, so that when a slave
　　# wants to reconnect again, often a fullresync is not needed, but a partial
　　# resync is enough, just passing theportion of data the slave missed while
　　# disconnected.[l70]
　　#
　　# Thebigger the replication backlog, the longer the time the slave can be
　　# disconnected and later be able toperform a partial resynchronization.[l71]
　　#
　　#The backlog is only allocated once there is at least a slave connected[l72] .
　　#
　　# repl-backlog-size 1mb
　　# Aftera master has no longer connected slaves for some time, the backlog
　　# will be freed. The following optionconfigures the amount of seconds that
　　# need to elapse, starting from the timethe last slave disconnected, for
　　# the backlog buffer to be freed.[l73]
　　#

　　# Avalue of 0 means to never>　　#
　　# repl-backlog-ttl 3600
　　# Theslave priority is an integer number published by Redis in the INFO output.
　　# It is used by Redis Sentinel in orderto select a slave to promote into a
　　# master if the master is no longerworking correctly.[l75]
　　#
　　# Aslave with a low priority number is considered better for promotion, so
　　# for instance if there are three slaveswith priority 10, 100, 25 Sentinel will
　　# pick the one with priority 10, that isthe lowest.[l76]
　　#
　　# Howevera special priority of 0 marks the slave as not able to perform the
　　# role of master, so a slave withpriority of 0 will never be selected by
　　# Redis Sentinel for promotion.[l77]
　　#
　　#By default the priority is 100.[l78]
　　slave-priority 100
　　# Itis possible for a master to stop accepting writes if there are less than
　　# N slaves connected, having a lag lessor equal than M seconds.[l79]
　　#
　　# TheN slaves need to be in "online" state.[l80]
　　#
　　# Thelag in seconds, that must be