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 20################################## INCLUDES ################################### 21 22# Include one or more other config files here. This is useful if you 23# have a standard template that goes to all Redis servers but also need 24# to customize a few per-server settings. Include files can include 25# other files, so use this wisely. 26# 27# Notice option "include" won't be rewritten by command "CONFIG REWRITE" 28# from admin or Redis Sentinel. Since Redis always uses the last processed 29# line as value of a configuration directive, you'd better put includes 30# at the beginning of this file to avoid overwriting config change at runtime. 31# 32# If instead you are interested in using includes to override configuration 33# options, it is better to use include as the last line. 34# 35# include /path/to/local.conf 36# include /path/to/other.conf 37 38################################## MODULES ##################################### 39 40# Load modules at startup. If the server is not able to load modules 41# it will abort. It is possible to use multiple loadmodule directives. 42# 43# loadmodule /path/to/my_module.so 44# loadmodule /path/to/other_module.so 45 46################################## NETWORK ##################################### 47 48# By default, if no "bind" configuration directive is specified, Redis listens 49# for connections from all the network interfaces available on the server. 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# 53# Examples: 54# 55# bind 192.168.1.100 10.0.0.1 56# bind 127.0.0.1 ::1 57# 58# ~~~ WARNING ~~~ If the computer running Redis is directly exposed to the 59# internet, binding to all the interfaces is dangerous and will expose the 60# instance to everybody on the internet. So by default we uncomment the 61# following bind directive, that will force Redis to listen only into 62# the IPv4 loopback interface address (this means Redis will be able to 63# accept connections only from clients running into the same computer it 64# is running). 65# 66# IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES 67# JUST COMMENT THE FOLLOWING LINE. 68# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 69bind 0.0.0.0 70 71# Protected mode is a layer of security protection, in order to avoid that 72# Redis instances left open on the internet are accessed and exploited. 73# 74# When protected mode is on and if: 75# 76# 1) The server is not binding explicitly to a set of addresses using the 77# "bind" directive. 78# 2) No password is configured. 79# 80# The server only accepts connections from clients connecting from the 81# IPv4 and IPv6 loopback addresses 127.0.0.1 and ::1, and from Unix domain 82# sockets. 83# 84# By default protected mode is enabled. You should disable it only if 85# you are sure you want clients from other hosts to connect to Redis 86# even if no authentication is configured, nor a specific set of interfaces 87# are explicitly listed using the "bind" directive. 88protected-mode no 89 90# Accept connections on the specified port, default is 6379 (IANA #815344). 91# If port 0 is specified Redis will not listen on a TCP socket. 92port 6379 93 94# TCP listen() backlog. 95# 96# In high requests-per-second environments you need an high backlog in order 97# to avoid slow clients connections issues. Note that the Linux kernel 98# will silently truncate it to the value of /proc/sys/net/core/somaxconn so 99# make sure to raise both the value of somaxconn and tcp_max_syn_backlog 100# in order to get the desired effect. 101tcp-backlog 511 102 103# Unix socket. 104# 105# Specify the path for the Unix socket that will be used to listen for 106# incoming connections. There is no default, so Redis will not listen 107# on a unix socket when not specified. 108# 109# unixsocket /tmp/redis.sock 110# unixsocketperm 700 111 112# Close the connection after a client is idle for N seconds (0 to disable) 113timeout 0 114 115# TCP keepalive. 116# 117# If non-zero, use SO_KEEPALIVE to send TCP ACKs to clients in absence 118# of communication. This is useful for two reasons: 119# 120# 1) Detect dead peers. 121# 2) Take the connection alive from the point of view of network 122# equipment in the middle. 123# 124# On Linux, the specified value (in seconds) is the period used to send ACKs. 125# Note that to close the connection the double of the time is needed. 126# On other kernels the period depends on the kernel configuration. 127# 128# A reasonable value for this option is 300 seconds, which is the new 129# Redis default starting with Redis 3.2.1. 130tcp-keepalive 300 131 132################################# GENERAL ##################################### 133 134# By default Redis does not run as a daemon. Use 'yes' if you need it. 135# Note that Redis will write a pid file in /var/run/redis.pid when daemonized. 136daemonize no 137 138# If you run Redis from upstart or systemd, Redis can interact with your 139# supervision tree. Options: 140# supervised no - no supervision interaction 141# supervised upstart - signal upstart by putting Redis into SIGSTOP mode 142# supervised systemd - signal systemd by writing READY=1 to $NOTIFY_SOCKET 143# supervised auto - detect upstart or systemd method based on 144# UPSTART_JOB or NOTIFY_SOCKET environment variables 145# Note: these supervision methods only signal "process is ready." 146# They do not enable continuous liveness pings back to your supervisor. 147supervised no 148 149# If a pid file is specified, Redis writes it where specified at startup 150# and removes it at exit. 151# 152# When the server runs non daemonized, no pid file is created if none is 153# specified in the configuration. When the server is daemonized, the pid file 154# is used even if not specified, defaulting to "/var/run/redis.pid". 155# 156# Creating a pid file is best effort: if Redis is not able to create it 157# nothing bad happens, the server will start and run normally. 158pidfile /var/run/redis_6379.pid 159 160# Specify the server verbosity level. 161# This can be one of: 162# debug (a lot of information, useful for development/testing) 163# verbose (many rarely useful info, but not a mess like the debug level) 164# notice (moderately verbose, what you want in production probably) 165# warning (only very important / critical messages are logged) 166loglevel notice 167 168# Specify the log file name. Also the empty string can be used to force 169# Redis to log on the standard output. Note that if you use standard 170# output for logging but daemonize, logs will be sent to /dev/null 171logfile "" 172 173# To enable logging to the system logger, just set 'syslog-enabled' to yes, 174# and optionally update the other syslog parameters to suit your needs. 175# syslog-enabled no 176 177# Specify the syslog identity. 178# syslog-ident redis 179 180# Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7. 181# syslog-facility local0 182 183# Set the number of databases. The default database is DB 0, you can select 184# a different one on a per-connection basis using SELECT <dbid> where 185# dbid is a number between 0 and 'databases'-1 186databases 16 187 188# By default Redis shows an ASCII art logo only when started to log to the 189# standard output and if the standard output is a TTY. Basically this means 190# that normally a logo is displayed only in interactive sessions. 191# 192# However it is possible to force the pre-4.0 behavior and always show a 193# ASCII art logo in startup logs by setting the following option to yes. 194always-show-logo yes 195 196################################ SNAPSHOTTING ################################ 197# 198# Save the DB on disk: 199# 200# save <seconds> <changes> 201# 202# Will save the DB if both the given number of seconds and the given 203# number of write operations against the DB occurred. 204# 205# In the example below the behaviour will be to save: 206# after 900 sec (15 min) if at least 1 key changed 207# after 300 sec (5 min) if at least 10 keys changed 208# after 60 sec if at least 10000 keys changed 209# 210# Note: you can disable saving completely by commenting out all "save" lines. 211# 212# It is also possible to remove all the previously configured save 213# points by adding a save directive with a single empty string argument 214# like in the following example: 215# 216# save "" 217 218save 900 1 219save 300 10 220save 60 10000 221 222# By default Redis will stop accepting writes if RDB snapshots are enabled 223# (at least one save point) and the latest background save failed. 224# This will make the user aware (in a hard way) that data is not persisting 225# on disk properly, otherwise chances are that no one will notice and some 226# disaster will happen. 227# 228# If the background saving process will start working again Redis will 229# automatically allow writes again. 230# 231# However if you have setup your proper monitoring of the Redis server 232# and persistence, you may want to disable this feature so that Redis will 233# continue to work as usual even if there are problems with disk, 234# permissions, and so forth. 235stop-writes-on-bgsave-error yes 236 237# Compress string objects using LZF when dump .rdb databases? 238# For default that's set to 'yes' as it's almost always a win. 239# If you want to save some CPU in the saving child set it to 'no' but 240# the dataset will likely be bigger if you have compressible values or keys. 241rdbcompression yes 242 243# Since version 5 of RDB a CRC64 checksum is placed at the end of the file. 244# This makes the format more resistant to corruption but there is a performance 245# hit to pay (around 10%) when saving and loading RDB files, so you can disable it 246# for maximum performances. 247# 248# RDB files created with checksum disabled have a checksum of zero that will 249# tell the loading code to skip the check. 250rdbchecksum yes 251 252# The filename where to dump the DB 253dbfilename dump.rdb 254 255# The working directory. 256# 257# The DB will be written inside this directory, with the filename specified 258# above using the 'dbfilename' configuration directive. 259# 260# The Append Only File will also be created inside this directory. 261# 262# Note that you must specify a directory here, not a file name. 263dir ./ 264 265################################# REPLICATION ################################# 266 267# Master-Replica replication. Use replicaof to make a Redis instance a copy of 268# another Redis server. A few things to understand ASAP about Redis replication. 269# 270# +------------------+ +---------------+ 271# | Master | ---> | Replica | 272# | (receive writes) | | (exact copy) | 273# +------------------+ +---------------+ 274# 275# 1) Redis replication is asynchronous, but you can configure a master to 276# stop accepting writes if it appears to be not connected with at least 277# a given number of replicas. 278# 2) Redis replicas are able to perform a partial resynchronization with the 279# master if the replication link is lost for a relatively small amount of 280# time. You may want to configure the replication backlog size (see the next 281# sections of this file) with a sensible value depending on your needs. 282# 3) Replication is automatic and does not need user intervention. After a 283# network partition replicas automatically try to reconnect to masters 284# and resynchronize with them. 285# 286# replicaof <masterip> <masterport> 287 288# If the master is password protected (using the "requirepass" configuration 289# directive below) it is possible to tell the replica to authenticate before 290# starting the replication synchronization process, otherwise the master will 291# refuse the replica request. 292# 293# masterauth <master-password> 294 295# When a replica loses its connection with the master, or when the replication 296# is still in progress, the replica can act in two different ways: 297# 298# 1) if replica-serve-stale-data is set to 'yes' (the default) the replica will 299# still reply to client requests, possibly with out of date data, or the 300# data set may just be empty if this is the first synchronization. 301# 302# 2) if replica-serve-stale-data is set to 'no' the replica will reply with 303# an error "SYNC with master in progress" to all the kind of commands 304# but to INFO, replicaOF, AUTH, PING, SHUTDOWN, REPLCONF, ROLE, CONFIG, 305# SUBSCRIBE, UNSUBSCRIBE, PSUBSCRIBE, PUNSUBSCRIBE, PUBLISH, PUBSUB, 306# COMMAND, POST, HOST: and LATENCY. 307# 308replica-serve-stale-data yes 309 310# You can configure a replica instance to accept writes or not. Writing against 311# a replica instance may be useful to store some ephemeral data (because data 312# written on a replica will be easily deleted after resync with the master) but 313# may also cause problems if clients are writing to it because of a 314# misconfiguration. 315# 316# Since Redis 2.6 by default replicas are read-only. 317# 318# Note: read only replicas are not designed to be exposed to untrusted clients 319# on the internet. It's just a protection layer against misuse of the instance. 320# Still a read only replica exports by default all the administrative commands 321# such as CONFIG, DEBUG, and so forth. To a limited extent you can improve 322# security of read only replicas using 'rename-command' to shadow all the 323# administrative / dangerous commands. 324replica-read-only yes 325 326# Replication SYNC strategy: disk or socket. 327# 328# ------------------------------------------------------- 329# WARNING: DISKLESS REPLICATION IS EXPERIMENTAL CURRENTLY 330# ------------------------------------------------------- 331# 332# New replicas and reconnecting replicas that are not able to continue the replication 333# process just receiving differences, need to do what is called a "full 334# synchronization". An RDB file is transmitted from the master to the replicas. 335# The transmission can happen in two different ways: 336# 337# 1) Disk-backed: The Redis master creates a new process that writes the RDB 338# file on disk. Later the file is transferred by the parent 339# process to the replicas incrementally. 340# 2) Diskless: The Redis master creates a new process that directly writes the 341# RDB file to replica sockets, without touching the disk at all. 342# 343# With disk-backed replication, while the RDB file is generated, more replicas 344# can be queued and served with the RDB file as soon as the current child producing 345# the RDB file finishes its work. With diskless replication instead once 346# the transfer starts, new replicas arriving will be queued and a new transfer 347# will start when the current one terminates. 348# 349# When diskless replication is used, the master waits a configurable amount of 350# time (in seconds) before starting the transfer in the hope that multiple replicas 351# will arrive and the transfer can be parallelized. 352# 353# With slow disks and fast (large bandwidth) networks, diskless replication 354# works better. 355repl-diskless-sync no 356 357# When diskless replication is enabled, it is possible to configure the delay 358# the server waits in order to spawn the child that transfers the RDB via socket 359# to the replicas. 360# 361# This is important since once the transfer starts, it is not possible to serve 362# new replicas arriving, that will be queued for the next RDB transfer, so the server 363# waits a delay in order to let more replicas arrive. 364# 365# The delay is specified in seconds, and by default is 5 seconds. To disable 366# it entirely just set it to 0 seconds and the transfer will start ASAP. 367repl-diskless-sync-delay 5 368 369# Replicas send PINGs to server in a predefined interval. It's possible to change 370# this interval with the repl_ping_replica_period option. The default value is 10 371# seconds. 372# 373# repl-ping-replica-period 10 374 375# The following option sets the replication timeout for: 376# 377# 1) Bulk transfer I/O during SYNC, from the point of view of replica. 378# 2) Master timeout from the point of view of replicas (data, pings). 379# 3) Replica timeout from the point of view of masters (REPLCONF ACK pings). 380# 381# It is important to make sure that this value is greater than the value 382# specified for repl-ping-replica-period otherwise a timeout will be detected 383# every time there is low traffic between the master and the replica. 384# 385# repl-timeout 60 386 387# Disable TCP_NODELAY on the replica socket after SYNC? 388# 389# If you select "yes" Redis will use a smaller number of TCP packets and 390# less bandwidth to send data to replicas. But this can add a delay for 391# the data to appear on the replica side, up to 40 milliseconds with 392# Linux kernels using a default configuration. 393# 394# If you select "no" the delay for data to appear on the replica side will 395# be reduced but more bandwidth will be used for replication. 396# 397# By default we optimize for low latency, but in very high traffic conditions 398# or when the master and replicas are many hops away, turning this to "yes" may 399# be a good idea. 400repl-disable-tcp-nodelay no 401 402# Set the replication backlog size. The backlog is a buffer that accumulates 403# replica data when replicas are disconnected for some time, so that when a replica 404# wants to reconnect again, often a full resync is not needed, but a partial 405# resync is enough, just passing the portion of data the replica missed while 406# disconnected. 407# 408# The bigger the replication backlog, the longer the time the replica can be 409# disconnected and later be able to perform a partial resynchronization. 410# 411# The backlog is only allocated once there is at least a replica connected. 412# 413# repl-backlog-size 1mb 414 415# After a master has no longer connected replicas for some time, the backlog 416# will be freed. The following option configures the amount of seconds that 417# need to elapse, starting from the time the last replica disconnected, for 418# the backlog buffer to be freed. 419# 420# Note that replicas never free the backlog for timeout, since they may be 421# promoted to masters later, and should be able to correctly "partially 422# resynchronize" with the replicas: hence they should always accumulate backlog. 423# 424# A value of 0 means to never release the backlog. 425# 426# repl-backlog-ttl 3600 427 428# The replica priority is an integer number published by Redis in the INFO output. 429# It is used by Redis Sentinel in order to select a replica to promote into a 430# master if the master is no longer working correctly. 431# 432# A replica with a low priority number is considered better for promotion, so 433# for instance if there are three replicas with priority 10, 100, 25 Sentinel will 434# pick the one with priority 10, that is the lowest. 435# 436# However a special priority of 0 marks the replica as not able to perform the 437# role of master, so a replica with priority of 0 will never be selected by 438# Redis Sentinel for promotion. 439# 440# By default the priority is 100. 441replica-priority 100 442 443# It is possible for a master to stop accepting writes if there are less than 444# N replicas connected, having a lag less or equal than M seconds. 445# 446# The N replicas need to be in "online" state. 447# 448# The lag in seconds, that must be <= the specified value, is calculated from 449# the last ping received from the replica, that is usually sent every second. 450# 451# This option does not GUARANTEE that N replicas will accept the write, but 452# will limit the window of exposure for lost writes in case not enough replicas 453# are available, to the specified number of seconds. 454# 455# For example to require at least 3 replicas with a lag <= 10 seconds use: 456# 457# min-replicas-to-write 3 458# min-replicas-max-lag 10 459# 460# Setting one or the other to 0 disables the feature. 461# 462# By default min-replicas-to-write is set to 0 (feature disabled) and 463# min-replicas-max-lag is set to 10. 464 465# A Redis master is able to list the address and port of the attached 466# replicas in different ways. For example the "INFO replication" section 467# offers this information, which is used, among other tools, by 468# Redis Sentinel in order to discover replica instances. 469# Another place where this info is available is in the output of the 470# "ROLE" command of a master. 471# 472# The listed IP and address normally reported by a replica is obtained 473# in the following way: 474# 475# IP: The address is auto detected by checking the peer address 476# of the socket used by the replica to connect with the master. 477# 478# Port: The port is communicated by the replica during the replication 479# handshake, and is normally the port that the replica is using to 480# listen for connections. 481# 482# However when port forwarding or Network Address Translation (NAT) is 483# used, the replica may be actually reachable via different IP and port 484# pairs. The following two options can be used by a replica in order to 485# report to its master a specific set of IP and port, so that both INFO 486# and ROLE will report those values. 487# 488# There is no need to use both the options if you need to override just 489# the port or the IP address. 490# 491# replica-announce-ip 5.5.5.5 492# replica-announce-port 1234 493 494################################## SECURITY ################################### 495 496# Require clients to issue AUTH <PASSWORD> before processing any other 497# commands. This might be useful in environments in which you do not trust 498# others with access to the host running redis-server. 499# 500# This should stay commented out for backward compatibility and because most 501# people do not need auth (e.g. they run their own servers). 502# 503# Warning: since Redis is pretty fast an outside user can try up to 504# 150k passwords per second against a good box. This means that you should 505# use a very strong password otherwise it will be very easy to break. 506# 507# requirepass foobared 508 509# Command renaming. 510# 511# It is possible to change the name of dangerous commands in a shared 512# environment. For instance the CONFIG command may be renamed into something 513# hard to guess so that it will still be available for internal-use tools 514# but not available for general clients. 515# 516# Example: 517# 518# rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52 519# 520# It is also possible to completely kill a command by renaming it into 521# an empty string: 522# 523# rename-command CONFIG "" 524# 525# Please note that changing the name of commands that are logged into the 526# AOF file or transmitted to replicas may cause problems. 527 528################################### CLIENTS #################################### 529 530# Set the max number of connected clients at the same time. By default 531# this limit is set to 10000 clients, however if the Redis server is not 532# able to configure the process file limit to allow for the specified limit 533# the max number of allowed clients is set to the current file limit 534# minus 32 (as Redis reserves a few file descriptors for internal uses). 535# 536# Once the limit is reached Redis will close all the new connections sending 537# an error 'max number of clients reached'. 538# 539# maxclients 10000 540 541############################## MEMORY MANAGEMENT ################################ 542 543# Set a memory usage limit to the specified amount of bytes. 544# When the memory limit is reached Redis will try to remove keys 545# according to the eviction policy selected (see maxmemory-policy). 546# 547# If Redis can't remove keys according to the policy, or if the policy is 548# set to 'noeviction', Redis will start to reply with errors to commands 549# that would use more memory, like SET, LPUSH, and so on, and will continue 550# to reply to read-only commands like GET. 551# 552# This option is usually useful when using Redis as an LRU or LFU cache, or to 553# set a hard memory limit for an instance (using the 'noeviction' policy). 554# 555# WARNING: If you have replicas attached to an instance with maxmemory on, 556# the size of the output buffers needed to feed the replicas are subtracted 557# from the used memory count, so that network problems / resyncs will 558# not trigger a loop where keys are evicted, and in turn the output 559# buffer of replicas is full with DELs of keys evicted triggering the deletion 560# of more keys, and so forth until the database is completely emptied. 561# 562# In short... if you have replicas attached it is suggested that you set a lower 563# limit for maxmemory so that there is some free RAM on the system for replica 564# output buffers (but this is not needed if the policy is 'noeviction'). 565# 566# maxmemory <bytes> 567 568# MAXMEMORY POLICY: how Redis will select what to remove when maxmemory 569# is reached. You can select among five behaviors: 570# 571# volatile-lru -> Evict using approximated LRU among the keys with an expire set. 572# allkeys-lru -> Evict any key using approximated LRU. 573# volatile-lfu -> Evict using approximated LFU among the keys with an expire set. 574# allkeys-lfu -> Evict any key using approximated LFU. 575# volatile-random -> Remove a random key among the ones with an expire set. 576# allkeys-random -> Remove a random key, any key. 577# volatile-ttl -> Remove the key with the nearest expire time (minor TTL) 578# noeviction -> Don't evict anything, just return an error on write operations. 579# 580# LRU means Least Recently Used 581# LFU means Least Frequently Used 582# 583# Both LRU, LFU and volatile-ttl are implemented using approximated 584# randomized algorithms. 585# 586# Note: with any of the above policies, Redis will return an error on write 587# operations, when there are no suitable keys for eviction. 588# 589# At the date of writing these commands are: set setnx setex append 590# incr decr rpush lpush rpushx lpushx linsert lset rpoplpush sadd 591# sinter sinterstore sunion sunionstore sdiff sdiffstore zadd zincrby 592# zunionstore zinterstore hset hsetnx hmset hincrby incrby decrby 593# getset mset msetnx exec sort 594# 595# The default is: 596# 597# maxmemory-policy noeviction 598 599# LRU, LFU and minimal TTL algorithms are not precise algorithms but approximated 600# algorithms (in order to save memory), so you can tune it for speed or 601# accuracy. For default Redis will check five keys and pick the one that was 602# used less recently, you can change the sample size using the following 603# configuration directive. 604# 605# The default of 5 produces good enough results. 10 Approximates very closely 606# true LRU but costs more CPU. 3 is faster but not very accurate. 607# 608# maxmemory-samples 5 609 610# Starting from Redis 5, by default a replica will ignore its maxmemory setting 611# (unless it is promoted to master after a failover or manually). It means 612# that the eviction of keys will be just handled by the master, sending the 613# DEL commands to the replica as keys evict in the master side. 614# 615# This behavior ensures that masters and replicas stay consistent, and is usually 616# what you want, however if your replica is writable, or you want the replica to have 617# a different memory setting, and you are sure all the writes performed to the 618# replica are idempotent, then you may change this default (but be sure to understand 619# what you are doing). 620# 621# Note that since the replica by default does not evict, it may end using more 622# memory than the one set via maxmemory (there are certain buffers that may 623# be larger on the replica, or data structures may sometimes take more memory and so 624# forth). So make sure you monitor your replicas and make sure they have enough 625# memory to never hit a real out-of-memory condition before the master hits 626# the configured maxmemory setting. 627# 628# replica-ignore-maxmemory yes 629 630############################# LAZY FREEING #################################### 631 632# Redis has two primitives to delete keys. One is called DEL and is a blocking 633# deletion of the object. It means that the server stops processing new commands 634# in order to reclaim all the memory associated with an object in a synchronous 635# way. If the key deleted is associated with a small object, the time needed 636# in order to execute the DEL command is very small and comparable to most other 637# O(1) or O(log_N) commands in Redis. However if the key is associated with an 638# aggregated value containing millions of elements, the server can block for 639# a long time (even seconds) in order to complete the operation. 640# 641# For the above reasons Redis also offers non blocking deletion primitives 642# such as UNLINK (non blocking DEL) and the ASYNC option of FLUSHALL and 643# FLUSHDB commands, in order to reclaim memory in background. Those commands 644# are executed in constant time. Another thread will incrementally free the 645# object in the background as fast as possible. 646# 647# DEL, UNLINK and ASYNC option of FLUSHALL and FLUSHDB are user-controlled. 648# It's up to the design of the application to understand when it is a good 649# idea to use one or the other. However the Redis server sometimes has to 650# delete keys or flush the whole database as a side effect of other operations. 651# Specifically Redis deletes objects independently of a user call in the 652# following scenarios: 653# 654# 1) On eviction, because of the maxmemory and maxmemory policy configurations, 655# in order to make room for new data, without going over the specified 656# memory limit. 657# 2) Because of expire: when a key with an associated time to live (see the 658# EXPIRE command) must be deleted from memory. 659# 3) Because of a side effect of a command that stores data on a key that may 660# already exist. For example the RENAME command may delete the old key 661# content when it is replaced with another one. Similarly SUNIONSTORE 662# or SORT with STORE option may delete existing keys. The SET command 663# itself removes any old content of the specified key in order to replace 664# it with the specified string. 665# 4) During replication, when a replica performs a full resynchronization with 666# its master, the content of the whole database is removed in order to 667# load the RDB file just transferred. 668# 669# In all the above cases the default is to delete objects in a blocking way, 670# like if DEL was called. However you can configure each case specifically 671# in order to instead release memory in a non-blocking way like if UNLINK 672# was called, using the following configuration directives: 673 674lazyfree-lazy-eviction no 675lazyfree-lazy-expire no 676lazyfree-lazy-server-del no 677replica-lazy-flush no 678 679############################## APPEND ONLY MODE ############################### 680 681# By default Redis asynchronously dumps the dataset on disk. This mode is 682# good enough in many applications, but an issue with the Redis process or 683# a power outage may result into a few minutes of writes lost (depending on 684# the configured save points). 685# 686# The Append Only File is an alternative persistence mode that provides 687# much better durability. For instance using the default data fsync policy 688# (see later in the config file) Redis can lose just one second of writes in a 689# dramatic event like a server power outage, or a single write if something 690# wrong with the Redis process itself happens, but the operating system is 691# still running correctly. 692# 693# AOF and RDB persistence can be enabled at the same time without problems. 694# If the AOF is enabled on startup Redis will load the AOF, that is the file 695# with the better durability guarantees. 696# 697# Please check http://redis.io/topics/persistence for more information. 698 699appendonly no 700 701# The name of the append only file (default: "appendonly.aof") 702 703appendfilename "appendonly.aof" 704 705# The fsync() call tells the Operating System to actually write data on disk 706# instead of waiting for more data in the output buffer. Some OS will really flush 707# data on disk, some other OS will just try to do it ASAP. 708# 709# Redis supports three different modes: 710# 711# no: don't fsync, just let the OS flush the data when it wants. Faster. 712# always: fsync after every write to the append only log. Slow, Safest. 713# everysec: fsync only one time every second. Compromise. 714# 715# The default is "everysec", as that's usually the right compromise between 716# speed and data safety. It's up to you to understand if you can relax this to 717# "no" that will let the operating system flush the output buffer when 718# it wants, for better performances (but if you can live with the idea of 719# some data loss consider the default persistence mode that's snapshotting), 720# or on the contrary, use "always" that's very slow but a bit safer than 721# everysec. 722# 723# More details please check the following article: 724# http://antirez.com/post/redis-persistence-demystified.html 725# 726# If unsure, use "everysec". 727 728# appendfsync always 729appendfsync everysec 730# appendfsync no 731 732# When the AOF fsync policy is set to always or everysec, and a background 733# saving process (a background save or AOF log background rewriting) is 734# performing a lot of I/O against the disk, in some Linux configurations 735# Redis may block too long on the fsync() call. Note that there is no fix for 736# this currently, as even performing fsync in a different thread will block 737# our synchronous write(2) call. 738# 739# In order to mitigate this problem it's possible to use the following option 740# that will prevent fsync() from being called in the main process while a 741# BGSAVE or BGREWRITEAOF is in progress. 742# 743# This means that while another child is saving, the durability of Redis is 744# the same as "appendfsync none". In practical terms, this means that it is 745# possible to lose up to 30 seconds of log in the worst scenario (with the 746# default Linux settings). 747# 748# If you have latency problems turn this to "yes". Otherwise leave it as 749# "no" that is the safest pick from the point of view of durability. 750 751no-appendfsync-on-rewrite no 752 753# Automatic rewrite of the append only file. 754# Redis is able to automatically rewrite the log file implicitly calling 755# BGREWRITEAOF when the AOF log size grows by the specified percentage. 756# 757# This is how it works: Redis remembers the size of the AOF file after the 758# latest rewrite (if no rewrite has happened since the restart, the size of 759# the AOF at startup is used). 760# 761# This base size is compared to the current size. If the current size is 762# bigger than the specified percentage, the rewrite is triggered. Also 763# you need to specify a minimal size for the AOF file to be rewritten, this 764# is useful to avoid rewriting the AOF file even if the percentage increase 765# is reached but it is still pretty small. 766# 767# Specify a percentage of zero in order to disable the automatic AOF 768# rewrite feature. 769 770auto-aof-rewrite-percentage 100 771auto-aof-rewrite-min-size 64mb 772 773# An AOF file may be found to be truncated at the end during the Redis 774# startup process, when the AOF data gets loaded back into memory. 775# This may happen when the system where Redis is running 776# crashes, especially when an ext4 filesystem is mounted without the 777# data=ordered option (however this can't happen when Redis itself 778# crashes or aborts but the operating system still works correctly). 779# 780# Redis can either exit with an error when this happens, or load as much 781# data as possible (the default now) and start if the AOF file is found 782# to be truncated at the end. The following option controls this behavior. 783# 784# If aof-load-truncated is set to yes, a truncated AOF file is loaded and 785# the Redis server starts emitting a log to inform the user of the event. 786# Otherwise if the option is set to no, the server aborts with an error 787# and refuses to start. When the option is set to no, the user requires 788# to fix the AOF file using the "redis-check-aof" utility before to restart 789# the server. 790# 791# Note that if the AOF file will be found to be corrupted in the middle 792# the server will still exit with an error. This option only applies when 793# Redis will try to read more data from the AOF file but not enough bytes 794# will be found. 795aof-load-truncated yes 796 797# When rewriting the AOF file, Redis is able to use an RDB preamble in the 798# AOF file for faster rewrites and recoveries. When this option is turned 799# on the rewritten AOF file is composed of two different stanzas: 800# 801# [RDB file][AOF tail] 802# 803# When loading Redis recognizes that the AOF file starts with the "REDIS" 804# string and loads the prefixed RDB file, and continues loading the AOF 805# tail. 806aof-use-rdb-preamble yes 807 808################################ LUA SCRIPTING ############################### 809 810# Max execution time of a Lua script in milliseconds. 811# 812# If the maximum execution time is reached Redis will log that a script is 813# still in execution after the maximum allowed time and will start to 814# reply to queries with an error. 815# 816# When a long running script exceeds the maximum execution time only the 817# SCRIPT KILL and SHUTDOWN NOSAVE commands are available. The first can be 818# used to stop a script that did not yet called write commands. The second 819# is the only way to shut down the server in the case a write command was 820# already issued by the script but the user doesn't want to wait for the natural 821# termination of the script. 822# 823# Set it to 0 or a negative value for unlimited execution without warnings. 824lua-time-limit 5000 825 826################################ REDIS CLUSTER ############################### 827 828# Normal Redis instances can't be part of a Redis Cluster; only nodes that are 829# started as cluster nodes can. In order to start a Redis instance as a 830# cluster node enable the cluster support uncommenting the following: 831# 832# cluster-enabled yes 833 834# Every cluster node has a cluster configuration file. This file is not 835# intended to be edited by hand. It is created and updated by Redis nodes. 836# Every Redis Cluster node requires a different cluster configuration file. 837# Make sure that instances running in the same system do not have 838# overlapping cluster configuration file names. 839# 840# cluster-config-file nodes-6379.conf 841 842# Cluster node timeout is the amount of milliseconds a node must be unreachable 843# for it to be considered in failure state. 844# Most other internal time limits are multiple of the node timeout. 845# 846# cluster-node-timeout 15000 847 848# A replica of a failing master will avoid to start a failover if its data 849# looks too old. 850# 851# There is no simple way for a replica to actually have an exact measure of 852# its "data age", so the following two checks are performed: 853# 854# 1) If there are multiple replicas able to failover, they exchange messages 855# in order to try to give an advantage to the replica with the best 856# replication offset (more data from the master processed). 857# Replicas will try to get their rank by offset, and apply to the start 858# of the failover a delay proportional to their rank. 859# 860# 2) Every single replica computes the time of the last interaction with 861# its master. This can be the last ping or command received (if the master 862# is still in the "connected" state), or the time that elapsed since the 863# disconnection with the master (if the replication link is currently down). 864# If the last interaction is too old, the replica will not try to failover 865# at all. 866# 867# The point "2" can be tuned by user. Specifically a replica will not perform 868# the failover if, since the last interaction with the master, the time 869# elapsed is greater than: 870# 871# (node-timeout * replica-validity-factor) + repl-ping-replica-period 872# 873# So for example if node-timeout is 30 seconds, and the replica-validity-factor 874# is 10, and assuming a default repl-ping-replica-period of 10 seconds, the 875# replica will not try to failover if it was not able to talk with the master 876# for longer than 310 seconds. 877# 878# A large replica-validity-factor may allow replicas with too old data to failover 879# a master, while a too small value may prevent the cluster from being able to 880# elect a replica at all. 881# 882# For maximum availability, it is possible to set the replica-validity-factor 883# to a value of 0, which means, that replicas will always try to failover the 884# master regardless of the last time they interacted with the master. 885# (However they'll always try to apply a delay proportional to their 886# offset rank). 887# 888# Zero is the only value able to guarantee that when all the partitions heal 889# the cluster will always be able to continue. 890# 891# cluster-replica-validity-factor 10 892 893# Cluster replicas are able to migrate to orphaned masters, that are masters 894# that are left without working replicas. This improves the cluster ability 895# to resist to failures as otherwise an orphaned master can't be failed over 896# in case of failure if it has no working replicas. 897# 898# Replicas migrate to orphaned masters only if there are still at least a 899# given number of other working replicas for their old master. This number 900# is the "migration barrier". A migration barrier of 1 means that a replica 901# will migrate only if there is at least 1 other working replica for its master 902# and so forth. It usually reflects the number of replicas you want for every 903# master in your cluster. 904# 905# Default is 1 (replicas migrate only if their masters remain with at least 906# one replica). To disable migration just set it to a very large value. 907# A value of 0 can be set but is useful only for debugging and dangerous 908# in production. 909# 910# cluster-migration-barrier 1 911 912# By default Redis Cluster nodes stop accepting queries if they detect there 913# is at least an hash slot uncovered (no available node is serving it). 914# This way if the cluster is partially down (for example a range of hash slots 915# are no longer covered) all the cluster becomes, eventually, unavailable. 916# It automatically returns available as soon as all the slots are covered again. 917# 918# However sometimes you want the subset of the cluster which is working, 919# to continue to accept queries for the part of the key space that is still 920# covered. In order to do so, just set the cluster-require-full-coverage 921# option to no. 922# 923# cluster-require-full-coverage yes 924 925# This option, when set to yes, prevents replicas from trying to failover its 926# master during master failures. However the master can still perform a 927# manual failover, if forced to do so. 928# 929# This is useful in different scenarios, especially in the case of multiple 930# data center operations, where we want one side to never be promoted if not 931# in the case of a total DC failure. 932# 933# cluster-replica-no-failover no 934 935# In order to setup your cluster make sure to read the documentation 936# available at http://redis.io web site. 937 938########################## CLUSTER DOCKER/NAT support ######################## 939 940# In certain deployments, Redis Cluster nodes address discovery fails, because 941# addresses are NAT-ted or because ports are forwarded (the typical case is 942# Docker and other containers). 943# 944# In order to make Redis Cluster working in such environments, a static 945# configuration where each node knows its public address is needed. The 946# following two options are used for this scope, and are: 947# 948# * cluster-announce-ip 949# * cluster-announce-port 950# * cluster-announce-bus-port 951# 952# Each instruct the node about its address, client port, and cluster message 953# bus port. The information is then published in the header of the bus packets 954# so that other nodes will be able to correctly map the address of the node 955# publishing the information. 956# 957# If the above options are not used, the normal Redis Cluster auto-detection 958# will be used instead. 959# 960# Note that when remapped, the bus port may not be at the fixed offset of 961# clients port + 10000, so you can specify any port and bus-port depending 962# on how they get remapped. If the bus-port is not set, a fixed offset of 963# 10000 will be used as usually. 964# 965# Example: 966# 967# cluster-announce-ip 10.1.1.5 968# cluster-announce-port 6379 969# cluster-announce-bus-port 6380 970 971################################## SLOW LOG ################################### 972 973# The Redis Slow Log is a system to log queries that exceeded a specified 974# execution time. The execution time does not include the I/O operations 975# like talking with the client, sending the reply and so forth, 976# but just the time needed to actually execute the command (this is the only 977# stage of command execution where the thread is blocked and can not serve 978# other requests in the meantime). 979# 980# You can configure the slow log with two parameters: one tells Redis 981# what is the execution time, in microseconds, to exceed in order for the 982# command to get logged, and the other parameter is the length of the 983# slow log. When a new command is logged the oldest one is removed from the 984# queue of logged commands. 985 986# The following time is expressed in microseconds, so 1000000 is equivalent 987# to one second. Note that a negative number disables the slow log, while 988# a value of zero forces the logging of every command. 989slowlog-log-slower-than 10000 990 991# There is no limit to this length. Just be aware that it will consume memory. 992# You can reclaim memory used by the slow log with SLOWLOG RESET. 993slowlog-max-len 128 994 995################################ LATENCY MONITOR ############################## 996 997# The Redis latency monitoring subsystem samples different operations 998# at runtime in order to collect data related to possible sources of 999# latency of a Redis instance. 1000# 1001# Via the LATENCY command this information is available to the user that can 1002# print graphs and obtain reports. 1003# 1004# The system only logs operations that were performed in a time equal or 1005# greater than the amount of milliseconds specified via the 1006# latency-monitor-threshold configuration directive. When its value is set 1007# to zero, the latency monitor is turned off. 1008# 1009# By default latency monitoring is disabled since it is mostly not needed 1010# if you don't have latency issues, and collecting data has a performance 1011# impact, that while very small, can be measured under big load. Latency 1012# monitoring can easily be enabled at runtime using the command 1013# "CONFIG SET latency-monitor-threshold <milliseconds>" if needed. 1014latency-monitor-threshold 0 1015 1016############################# EVENT NOTIFICATION ############################## 1017 1018# Redis can notify Pub/Sub clients about events happening in the key space. 1019# This feature is documented at http://redis.io/topics/notifications 1020# 1021# For instance if keyspace events notification is enabled, and a client 1022# performs a DEL operation on key "foo" stored in the Database 0, two 1023# messages will be published via Pub/Sub: 1024# 1025# PUBLISH __keyspace@0__:foo del 1026# PUBLISH __keyevent@0__:del foo 1027# 1028# It is possible to select the events that Redis will notify among a set 1029# of classes. Every class is identified by a single character: 1030# 1031# K Keyspace events, published with __keyspace@<db>__ prefix. 1032# E Keyevent events, published with __keyevent@<db>__ prefix. 1033# g Generic commands (non-type specific) like DEL, EXPIRE, RENAME, ... 1034# $ String commands 1035# l List commands 1036# s Set commands 1037# h Hash commands 1038# z Sorted set commands 1039# x Expired events (events generated every time a key expires) 1040# e Evicted events (events generated when a key is evicted for maxmemory) 1041# A Alias for g$lshzxe, so that the "AKE" string means all the events. 1042# 1043# The "notify-keyspace-events" takes as argument a string that is composed 1044# of zero or multiple characters. The empty string means that notifications 1045# are disabled. 1046# 1047# Example: to enable list and generic events, from the point of view of the 1048# event name, use: 1049# 1050# notify-keyspace-events Elg 1051# 1052# Example 2: to get the stream of the expired keys subscribing to channel 1053# name __keyevent@0__:expired use: 1054# 1055# notify-keyspace-events Ex 1056# 1057# By default all notifications are disabled because most users don't need 1058# this feature and the feature has some overhead. Note that if you don't 1059# specify at least one of K or E, no events will be delivered. 1060notify-keyspace-events "" 1061 1062############################### ADVANCED CONFIG ############################### 1063 1064# Hashes are encoded using a memory efficient data structure when they have a 1065# small number of entries, and the biggest entry does not exceed a given 1066# threshold. These thresholds can be configured using the following directives. 1067hash-max-ziplist-entries 512 1068hash-max-ziplist-value 64 1069 1070# Lists are also encoded in a special way to save a lot of space. 1071# The number of entries allowed per internal list node can be specified 1072# as a fixed maximum size or a maximum number of elements. 1073# For a fixed maximum size, use -5 through -1, meaning: 1074# -5: max size: 64 Kb <-- not recommended for normal workloads 1075# -4: max size: 32 Kb <-- not recommended 1076# -3: max size: 16 Kb <-- probably not recommended 1077# -2: max size: 8 Kb <-- good 1078# -1: max size: 4 Kb <-- good 1079# Positive numbers mean store up to _exactly_ that number of elements 1080# per list node. 1081# The highest performing option is usually -2 (8 Kb size) or -1 (4 Kb size), 1082# but if your use case is unique, adjust the settings as necessary. 1083list-max-ziplist-size -2 1084 1085# Lists may also be compressed. 1086# Compress depth is the number of quicklist ziplist nodes from *each* side of 1087# the list to *exclude* from compression. The head and tail of the list 1088# are always uncompressed for fast push/pop operations. Settings are: 1089# 0: disable all list compression 1090# 1: depth 1 means "don't start compressing until after 1 node into the list, 1091# going from either the head or tail" 1092# So: [head]->node->node->...->node->[tail] 1093# [head], [tail] will always be uncompressed; inner nodes will compress. 1094# 2: [head]->[next]->node->node->...->node->[prev]->[tail] 1095# 2 here means: don't compress head or head->next or tail->prev or tail, 1096# but compress all nodes between them. 1097# 3: [head]->[next]->[next]->node->node->...->node->[prev]->[prev]->[tail] 1098# etc. 1099list-compress-depth 0 1100 1101# Sets have a special encoding in just one case: when a set is composed 1102# of just strings that happen to be integers in radix 10 in the range 1103# of 64 bit signed integers. 1104# The following configuration setting sets the limit in the size of the 1105# set in order to use this special memory saving encoding. 1106set-max-intset-entries 512 1107 1108# Similarly to hashes and lists, sorted sets are also specially encoded in 1109# order to save a lot of space. This encoding is only used when the length and 1110# elements of a sorted set are below the following limits: 1111zset-max-ziplist-entries 128 1112zset-max-ziplist-value 64 1113 1114# HyperLogLog sparse representation bytes limit. The limit includes the 1115# 16 bytes header. When an HyperLogLog using the sparse representation crosses 1116# this limit, it is converted into the dense representation. 1117# 1118# A value greater than 16000 is totally useless, since at that point the 1119# dense representation is more memory efficient. 1120# 1121# The suggested value is ~ 3000 in order to have the benefits of 1122# the space efficient encoding without slowing down too much PFADD, 1123# which is O(N) with the sparse encoding. The value can be raised to 1124# ~ 10000 when CPU is not a concern, but space is, and the data set is 1125# composed of many HyperLogLogs with cardinality in the 0 - 15000 range. 1126hll-sparse-max-bytes 3000 1127 1128# Streams macro node max size / items. The stream data structure is a radix 1129# tree of big nodes that encode multiple items inside. Using this configuration 1130# it is possible to configure how big a single node can be in bytes, and the 1131# maximum number of items it may contain before switching to a new node when 1132# appending new stream entries. If any of the following settings are set to 1133# zero, the limit is ignored, so for instance it is possible to set just a 1134# max entires limit by setting max-bytes to 0 and max-entries to the desired 1135# value. 1136stream-node-max-bytes 4096 1137stream-node-max-entries 100 1138 1139# Active rehashing uses 1 millisecond every 100 milliseconds of CPU time in 1140# order to help rehashing the main Redis hash table (the one mapping top-level 1141# keys to values). The hash table implementation Redis uses (see dict.c) 1142# performs a lazy rehashing: the more operation you run into a hash table 1143# that is rehashing, the more rehashing "steps" are performed, so if the 1144# server is idle the rehashing is never complete and some more memory is used 1145# by the hash table. 1146# 1147# The default is to use this millisecond 10 times every second in order to 1148# actively rehash the main dictionaries, freeing memory when possible. 1149# 1150# If unsure: 1151# use "activerehashing no" if you have hard latency requirements and it is 1152# not a good thing in your environment that Redis can reply from time to time 1153# to queries with 2 milliseconds delay. 1154# 1155# use "activerehashing yes" if you don't have such hard requirements but 1156# want to free memory asap when possible. 1157activerehashing yes 1158 1159# The client output buffer limits can be used to force disconnection of clients 1160# that are not reading data from the server fast enough for some reason (a 1161# common reason is that a Pub/Sub client can't consume messages as fast as the 1162# publisher can produce them). 1163# 1164# The limit can be set differently for the three different classes of clients: 1165# 1166# normal -> normal clients including MONITOR clients 1167# replica -> replica clients 1168# pubsub -> clients subscribed to at least one pubsub channel or pattern 1169# 1170# The syntax of every client-output-buffer-limit directive is the following: 1171# 1172# client-output-buffer-limit <class> <hard limit> <soft limit> <soft seconds> 1173# 1174# A client is immediately disconnected once the hard limit is reached, or if 1175# the soft limit is reached and remains reached for the specified number of 1176# seconds (continuously). 1177# So for instance if the hard limit is 32 megabytes and the soft limit is 1178# 16 megabytes / 10 seconds, the client will get disconnected immediately 1179# if the size of the output buffers reach 32 megabytes, but will also get 1180# disconnected if the client reaches 16 megabytes and continuously overcomes 1181# the limit for 10 seconds. 1182# 1183# By default normal clients are not limited because they don't receive data 1184# without asking (in a push way), but just after a request, so only 1185# asynchronous clients may create a scenario where data is requested faster 1186# than it can read. 1187# 1188# Instead there is a default limit for pubsub and replica clients, since 1189# subscribers and replicas receive data in a push fashion. 1190# 1191# Both the hard or the soft limit can be disabled by setting them to zero. 1192client-output-buffer-limit normal 0 0 0 1193client-output-buffer-limit replica 256mb 64mb 60 1194client-output-buffer-limit pubsub 32mb 8mb 60 1195 1196# Client query buffers accumulate new commands. They are limited to a fixed 1197# amount by default in order to avoid that a protocol desynchronization (for 1198# instance due to a bug in the client) will lead to unbound memory usage in 1199# the query buffer. However you can configure it here if you have very special 1200# needs, such us huge multi/exec requests or alike. 1201# 1202# client-query-buffer-limit 1gb 1203 1204# In the Redis protocol, bulk requests, that are, elements representing single 1205# strings, are normally limited ot 512 mb. However you can change this limit 1206# here. 1207# 1208# proto-max-bulk-len 512mb 1209 1210# Redis calls an internal function to perform many background tasks, like 1211# closing connections of clients in timeout, purging expired keys that are 1212# never requested, and so forth. 1213# 1214# Not all tasks are performed with the same frequency, but Redis checks for 1215# tasks to perform according to the specified "hz" value. 1216# 1217# By default "hz" is set to 10. Raising the value will use more CPU when 1218# Redis is idle, but at the same time will make Redis more responsive when 1219# there are many keys expiring at the same time, and timeouts may be 1220# handled with more precision. 1221# 1222# The range is between 1 and 500, however a value over 100 is usually not 1223# a good idea. Most users should use the default of 10 and raise this up to 1224# 100 only in environments where very low latency is required. 1225hz 10 1226 1227# Normally it is useful to have an HZ value which is proportional to the 1228# number of clients connected. This is useful in order, for instance, to 1229# avoid too many clients are processed for each background task invocation 1230# in order to avoid latency spikes. 1231# 1232# Since the default HZ value by default is conservatively set to 10, Redis 1233# offers, and enables by default, the ability to use an adaptive HZ value 1234# which will temporary raise when there are many connected clients. 1235# 1236# When dynamic HZ is enabled, the actual configured HZ will be used as 1237# as a baseline, but multiples of the configured HZ value will be actually 1238# used as needed once more clients are connected. In this way an idle 1239# instance will use very little CPU time while a busy instance will be 1240# more responsive. 1241dynamic-hz yes 1242 1243# When a child rewrites the AOF file, if the following option is enabled 1244# the file will be fsync-ed every 32 MB of data generated. This is useful 1245# in order to commit the file to the disk more incrementally and avoid 1246# big latency spikes. 1247aof-rewrite-incremental-fsync yes 1248 1249# When redis saves RDB file, if the following option is enabled 1250# the file will be fsync-ed every 32 MB of data generated. This is useful 1251# in order to commit the file to the disk more incrementally and avoid 1252# big latency spikes. 1253rdb-save-incremental-fsync yes 1254 1255# Redis LFU eviction (see maxmemory setting) can be tuned. However it is a good 1256# idea to start with the default settings and only change them after investigating 1257# how to improve the performances and how the keys LFU change over time, which 1258# is possible to inspect via the OBJECT FREQ command. 1259# 1260# There are two tunable parameters in the Redis LFU implementation: the 1261# counter logarithm factor and the counter decay time. It is important to 1262# understand what the two parameters mean before changing them. 1263# 1264# The LFU counter is just 8 bits per key, it's maximum value is 255, so Redis 1265# uses a probabilistic increment with logarithmic behavior. Given the value 1266# of the old counter, when a key is accessed, the counter is incremented in 1267# this way: 1268# 1269# 1. A random number R between 0 and 1 is extracted. 1270# 2. A probability P is calculated as 1/(old_value*lfu_log_factor+1). 1271# 3. The counter is incremented only if R < P. 1272# 1273# The default lfu-log-factor is 10. This is a table of how the frequency 1274# counter changes with a different number of accesses with different 1275# logarithmic factors: 1276# 1277# +--------+------------+------------+------------+------------+------------+ 1278# | factor | 100 hits | 1000 hits | 100K hits | 1M hits | 10M hits | 1279# +--------+------------+------------+------------+------------+------------+ 1280# | 0 | 104 | 255 | 255 | 255 | 255 | 1281# +--------+------------+------------+------------+------------+------------+ 1282# | 1 | 18 | 49 | 255 | 255 | 255 | 1283# +--------+------------+------------+------------+------------+------------+ 1284# | 10 | 10 | 18 | 142 | 255 | 255 | 1285# +--------+------------+------------+------------+------------+------------+ 1286# | 100 | 8 | 11 | 49 | 143 | 255 | 1287# +--------+------------+------------+------------+------------+------------+ 1288# 1289# NOTE: The above table was obtained by running the following commands: 1290# 1291# redis-benchmark -n 1000000 incr foo 1292# redis-cli object freq foo 1293# 1294# NOTE 2: The counter initial value is 5 in order to give new objects a chance 1295# to accumulate hits. 1296# 1297# The counter decay time is the time, in minutes, that must elapse in order 1298# for the key counter to be divided by two (or decremented if it has a value 1299# less <= 10). 1300# 1301# The default value for the lfu-decay-time is 1. A Special value of 0 means to 1302# decay the counter every time it happens to be scanned. 1303# 1304# lfu-log-factor 10 1305# lfu-decay-time 1 1306 1307########################### ACTIVE DEFRAGMENTATION ####################### 1308# 1309# WARNING THIS FEATURE IS EXPERIMENTAL. However it was stress tested 1310# even in production and manually tested by multiple engineers for some 1311# time. 1312# 1313# What is active defragmentation? 1314# ------------------------------- 1315# 1316# Active (online) defragmentation allows a Redis server to compact the 1317# spaces left between small allocations and deallocations of data in memory, 1318# thus allowing to reclaim back memory. 1319# 1320# Fragmentation is a natural process that happens with every allocator (but 1321# less so with Jemalloc, fortunately) and certain workloads. Normally a server 1322# restart is needed in order to lower the fragmentation, or at least to flush 1323# away all the data and create it again. However thanks to this feature 1324# implemented by Oran Agra for Redis 4.0 this process can happen at runtime 1325# in an "hot" way, while the server is running. 1326# 1327# Basically when the fragmentation is over a certain level (see the 1328# configuration options below) Redis will start to create new copies of the 1329# values in contiguous memory regions by exploiting certain specific Jemalloc 1330# features (in order to understand if an allocation is causing fragmentation 1331# and to allocate it in a better place), and at the same time, will release the 1332# old copies of the data. This process, repeated incrementally for all the keys 1333# will cause the fragmentation to drop back to normal values. 1334# 1335# Important things to understand: 1336# 1337# 1. This feature is disabled by default, and only works if you compiled Redis 1338# to use the copy of Jemalloc we ship with the source code of Redis. 1339# This is the default with Linux builds. 1340# 1341# 2. You never need to enable this feature if you don't have fragmentation 1342# issues. 1343# 1344# 3. Once you experience fragmentation, you can enable this feature when 1345# needed with the command "CONFIG SET activedefrag yes". 1346# 1347# The configuration parameters are able to fine tune the behavior of the 1348# defragmentation process. If you are not sure about what they mean it is 1349# a good idea to leave the defaults untouched. 1350 1351# Enabled active defragmentation 1352# activedefrag yes 1353 1354# Minimum amount of fragmentation waste to start active defrag 1355# active-defrag-ignore-bytes 100mb 1356 1357# Minimum percentage of fragmentation to start active defrag 1358# active-defrag-threshold-lower 10 1359 1360# Maximum percentage of fragmentation at which we use maximum effort 1361# active-defrag-threshold-upper 100 1362 1363# Minimal effort for defrag in CPU percentage 1364# active-defrag-cycle-min 5 1365 1366# Maximal effort for defrag in CPU percentage 1367# active-defrag-cycle-max 75 1368 1369# Maximum number of set/hash/zset/list fields that will be processed from 1370# the main dictionary scan 1371# active-defrag-max-scan-fields 1000 1372 1373