# Redis configuration file example.
#
# Note that in order to read the configuration file, Redis must be
# started with the file path
as
first argument:
#
# ./redis-server /path/to/redis.conf
# Note on units: when memory size is needed, it is possible to specify
# it in the usual form of 1k 5GB 4M
and
so forth:
#
# 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.
################################## INCLUDES ###################################
# Include one
or
more other config files here. This is useful
if
you
# have a standard template that goes to all Redis servers but also need
# to customize a few per-server settings. Include files can
include
# other files, so
use
this wisely.
#
# Notice option
"include"
won't be rewritten by command
"CONFIG REWRITE"
# from admin
or
Redis Sentinel. Since Redis always uses the last processed
# line
as
value of a configuration directive, you'd better put includes
# at the beginning of this file to avoid overwriting config change at runtime.
#
# If instead you are interested in using includes to override configuration
# options, it is better to
use
include
as
the last line.
#
#
include
/path/to/local.conf
#
include
/path/to/other.conf
################################## MODULES #####################################
# Load modules at startup. If the server is not able to load modules
# it will abort. It is possible to
use
multiple loadmodule directives.
#
# loadmodule /path/to/my_module.so
# loadmodule /path/to/other_module.so
################################## NETWORK #####################################
# By
default
,
if
no
"bind"
configuration directive is specified, Redis listens
#
for
connections from all the network interfaces available on the server.
# It is possible to listen to just one
or
multiple selected interfaces using
# the
"bind"
configuration directive, followed by one
or
more IP addresses.
#
# Examples:
#
# bind 192.168.1.100 10.0.0.1
# bind 127.0.0.1 ::1
#
# ~~~ WARNING ~~~ If the computer running Redis is directly exposed to the
# internet, binding to all the interfaces is dangerous
and
will expose the
# instance to everybody on the internet. So by
default
we uncomment the
# following bind directive, that will force Redis to listen only into
# the IPv4 loopback
interface
address (this means Redis will be able to
# accept connections only from clients running into the same computer it
# is running).
#
# IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES
# JUST COMMENT THE FOLLOWING LINE.
# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#bind 127.0.0.1
# Protected mode is a layer of security protection, in order to avoid that
# Redis instances left open on the internet are accessed
and
exploited.
#
# When
protected
mode is on
and
if
:
#
# 1) The server is not binding explicitly to a set of addresses using the
#
"bind"
directive.
# 2) No password is configured.
#
# The server only accepts connections from clients connecting from the
# IPv4
and
IPv6 loopback addresses 127.0.0.1
and
::1,
and
from Unix domain
# sockets.
#
# By
default
protected
mode is enabled. You should disable it only
if
# you are sure you want clients from other hosts to connect to Redis
# even
if
no authentication is configured, nor a specific set of interfaces
# are explicitly listed using the
"bind"
directive.
protected
-mode no
# Accept connections on the specified port,
default
is 6379 (IANA #815344).
# If port 0 is specified Redis will not listen on a TCP socket.
port 6379
# TCP listen() backlog.
#
# In high requests-per-second environments you need an high backlog in order
# to avoid slow clients connections issues. Note that the Linux kernel
# will silently truncate it to the value of /proc/sys/net/core/somaxconn so
# make sure to raise both the value of somaxconn
and
tcp_max_syn_backlog
# in order to get the desired effect.
tcp-backlog 511
# Unix socket.
#
# 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 700
# Close the connection after a client is idle
for
N seconds (0 to disable)
timeout 0
# TCP keepalive.
#
# If non-zero,
use
SO_KEEPALIVE to send TCP ACKs to clients in absence
# of communication. This is useful
for
two reasons:
#
# 1) Detect dead peers.
# 2) Take the connection alive from the point of view of network
# equipment in the middle.
#
# On Linux, the specified value (in seconds) is the period used to send ACKs.
# Note that to close the connection the double of the time is needed.
# On other kernels the period depends on the kernel configuration.
#
# A reasonable value
for
this option is 300 seconds, which is the
new
# Redis
default
starting with Redis 3.2.1.
tcp-keepalive 300
################################# GENERAL #####################################
# By
default
Redis does not run
as
a daemon. Use 'yes'
if
you need it.
# Note that Redis will write a pid file in /
var
/run/redis.pid when daemonized.
daemonize no
# If you run Redis from upstart
or
systemd, Redis can interact with your
# supervision tree. Options:
# supervised no - no supervision interaction
# supervised upstart - signal upstart by putting Redis into SIGSTOP mode
# supervised systemd - signal systemd by writing READY=1 to
$NOTIFY_SOCKET
# supervised auto - detect upstart
or
systemd method based on
# UPSTART_JOB
or
NOTIFY_SOCKET environment variables
# Note: these supervision methods only signal
"process is ready."
# They
do
not enable continuous liveness pings back to your supervisor.
supervised no
# If a pid file is specified, Redis writes it where specified at startup
#
and
removes it at
exit
.
#
# When the server runs non daemonized, no pid file is created
if
none is
# specified in the configuration. When the server is daemonized, the pid file
# is used even
if
not specified, defaulting to
"/var/run/redis.pid"
.
#
# Creating a pid file is best effort:
if
Redis is not able to create it
# nothing bad happens, the server will start
and
run normally.
pidfile /
var
/run/redis_6379.pid
# Specify the server verbosity level.
# This can be one of:
# debug (a lot of information, useful
for
development/testing)
# verbose (many rarely useful info, but not a mess like the debug level)
# notice (moderately verbose, what you want in production probably)
# warning (only very important / critical messages are logged)
loglevel notice
# Specify the log file name. Also the
empty
string can be used to force
# Redis to log on the standard output. Note that
if
you
use
standard
# output
for
logging but daemonize, logs will be sent to /dev/null
logfile
""
# To enable logging to the system logger, just set 'syslog-enabled' to yes,
#
and
optionally update the other syslog parameters to suit your needs.
# syslog-enabled no
# Specify the syslog identity.
# syslog-ident redis
# Specify the syslog facility. Must be USER
or
between LOCAL0-LOCAL7.
# syslog-facility local0
# Set the number of databases. The
default
database is DB 0, you can select
# a different one on a per-connection basis using SELECT <dbid> where
# dbid is a number between 0
and
'databases'-1
databases 16
# By
default
Redis shows an ASCII art logo only when started to log to the
# standard output
and
if
the standard output is a TTY. Basically this means
# that normally a logo is displayed only in interactive sessions.
#
# However it is possible to force the pre-4.0 behavior
and
always show a
# ASCII art logo in startup logs by setting the following option to yes.
always-show-logo yes
################################ SNAPSHOTTING ################################
#
# 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.
#
# In the example below the behaviour will be to save:
# after 900 sec (15 min)
if
at least 1 key changed
# after 300 sec (5 min)
if
at least 10 keys changed
# after 60 sec
if
at least 10000 keys changed
#
# Note: you can disable saving completely by commenting out all
"save"
lines.
#
# It is also possible to remove all the previously configured save
# points by adding a save directive with a single
empty
string argument
# like in the following example:
#
# save
""
save 900 1
save 300 10
save 60 10000
# By
default
Redis will stop accepting writes
if
RDB snapshots are enabled
# (at least one save point)
and
the latest background save failed.
# This will make the user aware (in a hard way) that data is not persisting
# on disk properly, otherwise chances are that no one will notice
and
some
# disaster will happen.
#
# If the background saving process will start working again Redis will
# automatically allow writes again.
#
# However
if
you have setup your proper monitoring of the Redis server
#
and
persistence, you may want to disable this feature so that Redis will
#
continue
to work
as
usual even
if
there are problems with disk,
# permissions,
and
so forth.
stop-writes-on-bgsave-error yes
# Compress string objects using LZF when dump .rdb databases?
# For
default
that's set to 'yes'
as
it's almost always a win.
# If you want to save some CPU in the saving child set it to 'no' but
# the dataset will likely be bigger
if
you have compressible values
or
keys.
rdbcompression yes
# Since version 5 of RDB a CRC64 checksum is placed at the
end
of the file.
# This makes the format more resistant to corruption but there is a performance
# hit to pay (around 10%) when saving
and
loading RDB files, so you can disable it
#
for
maximum performances.
#
# RDB files created with checksum disabled have a checksum of zero that will
# tell the loading code to skip the check.
rdbchecksum yes
# The filename where to dump the DB
dbfilename dump.rdb
# The working directory.
#
# The DB will be written inside this directory, with the filename specified
# above using the 'dbfilename' configuration directive.
#
# The Append Only File will also be created inside this directory.
#
# Note that you must specify a directory here, not a file name.
dir ./
################################# REPLICATION #################################
# Master-Replica replication. Use replicaof to make a Redis instance a
copy
of
# another Redis server. A few things to understand ASAP about Redis replication.
#
# +------------------+ +---------------+
# | Master | ---> | Replica |
# | (receive writes) | | (exact
copy
) |
# +------------------+ +---------------+
#
# 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 replicas.
# 2) Redis replicas are able to perform a partial resynchronization with the
# master
if
the replication link is lost
for
a relatively small amount of
# time. You may want to configure the replication backlog size (see the next
# sections of this file) with a sensible value depending on your needs.
# 3) Replication is automatic
and
does not need user intervention. After a
# network partition replicas automatically
try
to reconnect to masters
#
and
resynchronize with them.
#
# replicaof <masterip> <masterport>
# If the master is password
protected
(using the
"requirepass"
configuration
# directive below) it is possible to tell the replica to authenticate before
# starting the replication synchronization process, otherwise the master will
# refuse the replica request.
#
# masterauth <master-password>
# When a replica loses its connection with the master,
or
when the replication
# is still in progress, the replica can act in two different ways:
#
# 1)
if
replica-serve-stale-data is set to 'yes' (the
default
) the replica 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.
#
# 2)
if
replica-serve-stale-data is set to 'no' the replica will reply with
# an error
"SYNC with master in progress"
to all the kind of commands
# but to INFO, replicaOF, AUTH, PING, SHUTDOWN, REPLCONF, ROLE, CONFIG,
# SUBSCRIBE, UNSUBSCRIBE, PSUBSCRIBE, PUNSUBSCRIBE, PUBLISH, PUBSUB,
# COMMAND, POST, HOST:
and
LATENCY.
#
replica-serve-stale-data yes
# You can configure a replica instance to accept writes
or
not. Writing against
# a replica instance may be useful to store some ephemeral data (because data
# written on a replica will be easily deleted after resync with the master) but
# may also cause problems
if
clients are writing to it because of a
# misconfiguration.
#
# Since Redis 2.6 by
default
replicas are read-only.
#
# Note: read only replicas are not designed to be exposed to untrusted clients
# on the internet. It's just a protection layer against misuse of the instance.
# Still a read only replica exports by
default
all the administrative commands
# such
as
CONFIG, DEBUG,
and
so forth. To a limited extent you can improve
# security of read only replicas using 'rename-command' to shadow all the
# administrative / dangerous commands.
replica-read-only yes
# Replication SYNC strategy: disk
or
socket.
#
# -------------------------------------------------------
# WARNING: DISKLESS REPLICATION IS EXPERIMENTAL CURRENTLY
# -------------------------------------------------------
#
# New replicas
and
reconnecting replicas that are not able to
continue
the replication
# process just receiving differences, need to
do
what is called a "full
# synchronization". An RDB file is transmitted from the master to the replicas.
# The transmission can happen in two different ways:
#
# 1) Disk-backed: The Redis master creates a
new
process that writes the RDB
# file on disk. Later the file is transferred by the parent
# process to the replicas incrementally.
# 2) Diskless: The Redis master creates a
new
process that directly writes the
# RDB file to replica sockets, without touching the disk at all.
#
# With disk-backed replication,
while
the RDB file is generated, more replicas
# can be queued
and
served with the RDB file
as
soon
as
the current child producing
# the RDB file finishes its work. With diskless replication instead once
# the transfer starts,
new
replicas arriving will be queued
and
a
new
transfer
# will start when the current one terminates.
#
# When diskless replication is used, the master waits a configurable amount of
# time (in seconds) before starting the transfer in the hope that multiple replicas
# will arrive
and
the transfer can be parallelized.
#
# With slow disks
and
fast (large bandwidth) networks, diskless replication
# works better.
repl-diskless-sync no
# When diskless replication is enabled, it is possible to configure the delay
# the server waits in order to spawn the child that transfers the RDB via socket
# to the replicas.
#
# This is important since once the transfer starts, it is not possible to serve
#
new
replicas arriving, that will be queued
for
the next RDB transfer, so the server
# waits a delay in order to let more replicas arrive.
#
# The delay is specified in seconds,
and
by
default
is 5 seconds. To disable
# it entirely just set it to 0 seconds
and
the transfer will start ASAP.
repl-diskless-sync-delay 5
# Replicas send PINGs to server in a predefined interval. It's possible to change
# this interval with the repl_ping_replica_period option. The
default
value is 10
# seconds.
#
# repl-ping-replica-period 10
# The following option sets the replication timeout
for
:
#
# 1) Bulk transfer I/O during SYNC, from the point of view of replica.
# 2) Master timeout from the point of view of replicas (data, pings).
# 3) Replica timeout from the point of view of masters (REPLCONF ACK pings).
#
# It is important to make sure that this value is greater than the value
# specified
for
repl-ping-replica-period otherwise a timeout will be detected
# every time there is low traffic between the master
and
the replica.
#
# repl-timeout 60
# Disable TCP_NODELAY on the replica socket after SYNC?
#
# If you select
"yes"
Redis will
use
a smaller number of TCP packets
and
# less bandwidth to send data to replicas. But this can add a delay
for
# the data to appear on the replica side, up to 40 milliseconds with
# Linux kernels using a
default
configuration.
#
# If you select
"no"
the delay
for
data to appear on the replica side will
# be reduced but more bandwidth will be used
for
replication.
#
# By
default
we optimize
for
low latency, but in very high traffic conditions
#
or
when the master
and
replicas are many hops away, turning this to
"yes"
may
# be a good idea.
repl-disable-tcp-nodelay no
# Set the replication backlog size. The backlog is a buffer that accumulates
# replica data when replicas are disconnected
for
some time, so that when a replica
# wants to reconnect again, often a full resync is not needed, but a partial
# resync is enough, just passing the portion of data the replica missed
while
# disconnected.
#
# The bigger the replication backlog, the longer the time the replica can be
# disconnected
and
later be able to perform a partial resynchronization.
#
# The backlog is only allocated once there is at least a replica connected.
#
# repl-backlog-size 1mb
# After a master has no longer connected replicas
for
some time, the backlog
# will be freed. The following option configures the amount of seconds that
# need to elapse, starting from the time the last replica disconnected,
for
# the backlog buffer to be freed.
#
# Note that replicas never free the backlog
for
timeout, since they may be
# promoted to masters later,
and
should be able to correctly "partially
# resynchronize" with the replicas: hence they should always accumulate backlog.
#
# A value of 0 means to never release the backlog.
#
# repl-backlog-ttl 3600
# The replica priority is an integer number published by Redis in the INFO output.
# It is used by Redis Sentinel in order to select a replica to promote into a
# master
if
the master is no longer working correctly.
#
# A replica with a low priority number is considered better
for
promotion, so
#
for
instance
if
there are three replicas with priority 10, 100, 25 Sentinel will
# pick the one with priority 10, that is the lowest.
#
# However a special priority of 0 marks the replica
as
not able to perform the
# role of master, so a replica with priority of 0 will never be selected by
# Redis Sentinel
for
promotion.
#
# By
default
the priority is 100.
replica-priority 100
# It is possible
for
a master to stop accepting writes
if
there are less than
# N replicas connected, having a lag less
or
equal than M seconds.
#
# The N replicas need to be in
"online"
state.
#
# The lag in seconds, that must be <= the specified value, is calculated from
# the last ping received from the replica, that is usually sent every second.
#
# This option does not GUARANTEE that N replicas will accept the write, but
# will limit the window of exposure
for
lost writes in
case
not enough replicas
# are available, to the specified number of seconds.
#
# For example to
require
at least 3 replicas with a lag <= 10 seconds
use
:
#
# min-replicas-to-write 3
# min-replicas-max-lag 10
#
# Setting one
or
the other to 0 disables the feature.
#
# By
default
min-replicas-to-write is set to 0 (feature disabled)
and
# min-replicas-max-lag is set to 10.
# A Redis master is able to list the address
and
port of the attached
# replicas in different ways. For example the
"INFO replication"
section
# offers this information, which is used, among other tools, by
# Redis Sentinel in order to discover replica instances.
# Another place where this info is available is in the output of the
#
"ROLE"
command of a master.
#
# The listed IP
and
address normally reported by a replica is obtained
# in the following way:
#
# IP: The address is auto detected by checking the peer address
# of the socket used by the replica to connect with the master.
#
# Port: The port is communicated by the replica during the replication
# handshake,
and
is normally the port that the replica is using to
# listen
for
connections.
#
# However when port forwarding
or
Network Address Translation (NAT) is
# used, the replica may be actually reachable via different IP
and
port
# pairs. The following two options can be used by a replica in order to
# report to its master a specific set of IP
and
port, so that both INFO
#
and
ROLE will report those values.
#
# There is no need to
use
both the options
if
you need to override just
# the port
or
the IP address.
#
# replica-announce-ip 5.5.5.5
# replica-announce-port 1234
################################## SECURITY ###################################
# Require clients to issue AUTH <PASSWORD> before processing any other
# commands. This might be useful in environments in which you
do
not trust
# others with access to the host running redis-server.
#
# This should stay commented out
for
backward compatibility
and
because most
# people
do
not need auth (e.g. they run their own servers).
#
# 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
.
#
# requirepass foobared
# Command renaming.
#
# It is possible to change the name of dangerous commands in a shared
# environment. For instance the CONFIG command may be renamed into something
# hard to guess so that it will still be available
for
internal-
use
tools
# but not available
for
general clients.
#
# Example:
#
# rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52
#
# It is also possible to completely kill a command by renaming it into
# an
empty
string:
#
# rename-command CONFIG
""
#
# Please note that changing the name of commands that are logged into the
# AOF file
or
transmitted to replicas may cause problems.
################################### CLIENTS ####################################
# Set the max number of connected clients at the same time. By
default
# this limit is set to 10000 clients, however
if
the Redis server is not
# able to configure the process file limit to allow
for
the specified limit
# the max number of allowed clients is set to the current file limit
# minus 32 (
as
Redis reserves a few file descriptors
for
internal uses).
#
# Once the limit is reached Redis will close all the
new
connections sending
# an error 'max number of clients reached'.
#
# maxclients 10000
############################## MEMORY MANAGEMENT ################################
# Set a memory usage limit to the specified amount of bytes.
# When the memory limit is reached Redis will
try
to remove keys
# according to the eviction policy selected (see maxmemory-policy).
#
# If Redis can't remove keys according to the policy,
or
if
the policy is
# set to 'noeviction', Redis will start to reply with errors to commands
# that would
use
more memory, like SET, LPUSH,
and
so on,
and
will
continue
# to reply to read-only commands like GET.
#
# This option is usually useful when using Redis
as
an LRU
or
LFU cache,
or
to
# set a hard memory limit
for
an instance (using the 'noeviction' policy).
#
# WARNING: If you have replicas attached to an instance with maxmemory on,
# the size of the output buffers needed to feed the replicas are subtracted
# from the used memory
count
, so that network problems / resyncs will
# not trigger a loop where keys are evicted,
and
in turn the output
# buffer of replicas is full with DELs of keys evicted triggering the deletion
# of more keys,
and
so forth until the database is completely emptied.
#
# In short...
if
you have replicas attached it is suggested that you set a lower
# limit
for
maxmemory so that there is some free RAM on the system
for
replica
# output buffers (but this is not needed
if
the policy is 'noeviction').
#
# maxmemory <bytes>
# MAXMEMORY POLICY: how Redis will select what to remove when maxmemory
# is reached. You can select among five behaviors:
#
# volatile-lru -> Evict using approximated LRU among the keys with an expire set.
# allkeys-lru -> Evict any key using approximated LRU.
# volatile-lfu -> Evict using approximated LFU among the keys with an expire set.
# allkeys-lfu -> Evict any key using approximated LFU.
# volatile-random -> Remove a random key among the ones 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 evict anything, just
return
an error on write operations.
#
# LRU means Least Recently Used
# LFU means Least Frequently Used
#
# Both LRU, LFU
and
volatile-ttl are implemented using approximated
# randomized algorithms.
#
# Note: with any of the above policies, Redis will
return
an error on write
# operations, when there are no suitable keys
for
eviction.
#
# At the
date
of writing these 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 noeviction
# LRU, LFU
and
minimal TTL algorithms are not precise algorithms but approximated
# algorithms (in order to save memory), so you can tune it
for
speed
or
# accuracy. For
default
Redis will check five keys
and
pick the one that was
# used less recently, you can change the sample size using the following
# configuration directive.
#
# The
default
of 5 produces good enough results. 10 Approximates very closely
# true LRU but costs more CPU. 3 is faster but not very accurate.
#
# maxmemory-samples 5
# Starting from Redis 5, by
default
a replica will ignore its maxmemory setting
# (unless it is promoted to master after a failover
or
manually). It means
# that the eviction of keys will be just handled by the master, sending the
# DEL commands to the replica
as
keys evict in the master side.
#
# This behavior ensures that masters
and
replicas stay consistent,
and
is usually
# what you want, however
if
your replica is writable,
or
you want the replica to have
# a different memory setting,
and
you are sure all the writes performed to the
# replica are idempotent, then you may change this
default
(but be sure to understand
# what you are doing).
#
# Note that since the replica by
default
does not evict, it may
end
using more
# memory than the one set via maxmemory (there are certain buffers that may
# be larger on the replica,
or
data structures may sometimes take more memory
and
so
# forth). So make sure you monitor your replicas
and
make sure they have enough
# memory to never hit a real out-of-memory condition before the master hits
# the configured maxmemory setting.
#
# replica-ignore-maxmemory yes
############################# LAZY FREEING ####################################
# Redis has two primitives to
delete
keys. One is called DEL
and
is a blocking
# deletion of the object. It means that the server stops processing
new
commands
# in order to reclaim all the memory associated with an object in a synchronous
# way. If the key deleted is associated with a small object, the time needed
# in order to execute the DEL command is very small
and
comparable to most other
# O(1)
or
O(log_N) commands in Redis. However
if
the key is associated with an
# aggregated value containing millions of elements, the server can block
for
# a long time (even seconds) in order to complete the operation.
#
# For the above reasons Redis also offers non blocking deletion primitives
# such
as
UNLINK (non blocking DEL)
and
the ASYNC option of FLUSHALL
and
# FLUSHDB commands, in order to reclaim memory in background. Those commands
# are executed in constant time. Another thread will incrementally free the
# object in the background
as
fast
as
possible.
#
# DEL, UNLINK
and
ASYNC option of FLUSHALL
and
FLUSHDB are user-controlled.
# It's up to the design of the application to understand when it is a good
# idea to
use
one
or
the other. However the Redis server sometimes has to
#
delete
keys
or
flush
the whole database
as
a side effect of other operations.
# Specifically Redis deletes objects independently of a user call in the
# following scenarios:
#
# 1) On eviction, because of the maxmemory
and
maxmemory policy configurations,
# in order to make room
for
new
data, without going over the specified
# memory limit.
# 2) Because of expire: when a key with an associated time to live (see the
# EXPIRE command) must be deleted from memory.
# 3) Because of a side effect of a command that stores data on a key that may
# already exist. For example the RENAME command may
delete
the old key
# content when it is replaced with another one. Similarly SUNIONSTORE
#
or
SORT with STORE option may
delete
existing keys. The SET command
# itself removes any old content of the specified key in order to replace
# it with the specified string.
# 4) During replication, when a replica performs a full resynchronization with
# its master, the content of the whole database is removed in order to
# load the RDB file just transferred.
#
# In all the above cases the
default
is to
delete
objects in a blocking way,
# like
if
DEL was called. However you can configure each
case
specifically
# in order to instead release memory in a non-blocking way like
if
UNLINK
# was called, using the following configuration directives:
lazyfree-lazy-eviction no
lazyfree-lazy-expire no
lazyfree-lazy-server-del no
replica-lazy-
flush
no
############################## APPEND ONLY MODE ###############################
# By
default
Redis asynchronously dumps the dataset on disk. This mode is
# good enough in many applications, but an issue with the Redis process
or
# a power outage may result into a few minutes of writes lost (depending on
# the configured save points).
#
# The Append Only File is an alternative persistence mode that provides
# much better durability. For instance using the
default
data fsync policy
# (see later in the config file) Redis can lose just one second of writes in a
# dramatic event like a server power outage,
or
a single write
if
something
# wrong with the Redis process itself happens, but the operating system is
# still running correctly.
#
# AOF
and
RDB persistence can be enabled at the same time without problems.
# If the AOF is enabled on startup Redis will load the AOF, that is the file
# with the better durability guarantees.
#
# Please check http:
appendonly no
# The name of the append only file (
default
:
"appendonly.aof"
)
appendfilename
"appendonly.aof"
# The fsync() call tells the Operating System to actually write data on disk
# instead of waiting
for
more data in the output buffer. Some OS will really
flush
# data on disk, some other OS will just
try
to
do
it ASAP.
#
# Redis supports three different modes:
#
# no: don't fsync, just let the OS
flush
the data when it wants. Faster.
# always: fsync after every write to the append only log. Slow, Safest.
# everysec: fsync only one time every second. Compromise.
#
# The
default
is
"everysec"
,
as
that's usually the right compromise between
# speed
and
data safety. It's up to you to understand
if
you can relax this to
#
"no"
that will let the operating system
flush
the output buffer when
# it wants,
for
better performances (but
if
you can live with the idea of
# some data loss consider the
default
persistence mode that's snapshotting),
#
or
on the contrary,
use
"always"
that's very slow but a bit safer than
# everysec.
#
# More details please check the following article:
# http:
#
# If unsure,
use
"everysec"
.
# appendfsync always
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"
. In practical terms, this means that it is
# possible to lose 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 grows by the specified percentage.
#
# This is how it works: Redis remembers the size of the AOF file after the
# latest rewrite (
if
no rewrite has 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 percentage of zero in order to disable the automatic AOF
# rewrite feature.
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb
# An AOF file may be found to be truncated at the
end
during the Redis
# startup process, when the AOF data gets loaded back into memory.
# This may happen when the system where Redis is running
# crashes, especially when an ext4 filesystem is mounted without the
# data=ordered option (however this can't happen when Redis itself
# crashes
or
aborts but the operating system still works correctly).
#
# Redis can either
exit
with an error when this happens,
or
load
as
much
# data
as
possible (the
default
now)
and
start
if
the AOF file is found
# to be truncated at the
end
. The following option controls this behavior.
#
# If aof-load-truncated is set to yes, a truncated AOF file is loaded
and
# the Redis server starts emitting a log to inform the user of the event.
# Otherwise
if
the option is set to no, the server aborts with an error
#
and
refuses to start. When the option is set to no, the user requires
# to fix the AOF file using the
"redis-check-aof"
utility before to restart
# the server.
#
# Note that
if
the AOF file will be found to be corrupted in the middle
# the server will still
exit
with an error. This option only applies when
# Redis will
try
to read more data from the AOF file but not enough bytes
# will be found.
aof-load-truncated yes
# When rewriting the AOF file, Redis is able to
use
an RDB preamble in the
# AOF file
for
faster rewrites
and
recoveries. When this option is turned
# on the rewritten AOF file is composed of two different stanzas:
#
# [RDB file][AOF tail]
#
# When loading Redis recognizes that the AOF file starts with the
"REDIS"
# string
and
loads the prefixed RDB file,
and
continues loading the AOF
# tail.
aof-
use
-rdb-preamble yes
################################ LUA SCRIPTING ###############################
# Max execution time of a Lua script in milliseconds.
#
# If the maximum execution time is reached Redis will log that a script is
# still in execution after the maximum allowed time
and
will start to
# reply to queries with an error.
#
# When a long running script exceeds the maximum execution time only the
# SCRIPT KILL
and
SHUTDOWN NOSAVE commands are available. The first can be
# used to stop a script that did not yet called write commands. The second
# is the only way to shut down the server in the
case
a write command was
# already issued by the script but the user doesn't want to wait
for
the natural
# termination of the script.
#
# Set it to 0
or
a negative value
for
unlimited execution without warnings.
lua-time-limit 5000
################################ REDIS CLUSTER ###############################
# Normal Redis instances can't be part of a Redis Cluster; only nodes that are
# started
as
cluster nodes can. In order to start a Redis instance
as
a
# cluster node enable the cluster support uncommenting the following:
#
# cluster-enabled yes
# Every cluster node has a cluster configuration file. This file is not
# intended to be edited by hand. It is created
and
updated by Redis nodes.
# Every Redis Cluster node requires a different cluster configuration file.
# Make sure that instances running in the same system
do
not have
# overlapping cluster configuration file names.
#
# cluster-config-file nodes-6379.conf
# Cluster node timeout is the amount of milliseconds a node must be unreachable
#
for
it to be considered in failure state.
# Most other internal time limits are multiple of the node timeout.
#
# cluster-node-timeout 15000
# A replica of a failing master will avoid to start a failover
if
its data
# looks too old.
#
# There is no simple way
for
a replica to actually have an exact measure of
# its
"data age"
, so the following two checks are performed:
#
# 1) If there are multiple replicas able to failover, they exchange messages
# in order to
try
to give an advantage to the replica with the best
# replication offset (more data from the master processed).
# Replicas will
try
to get their rank by offset,
and
apply to the start
# of the failover a delay proportional to their rank.
#
# 2) Every single replica computes the time of the last interaction with
# its master. This can be the last ping
or
command received (
if
the master
# is still in the
"connected"
state),
or
the time that elapsed since the
# disconnection with the master (
if
the replication link is currently down).
# If the last interaction is too old, the replica will not
try
to failover
# at all.
#
# The point
"2"
can be tuned by user. Specifically a replica will not perform
# the failover
if
, since the last interaction with the master, the time
# elapsed is greater than:
#
# (node-timeout * replica-validity-factor) + repl-ping-replica-period
#
# So
for
example
if
node-timeout is 30 seconds,
and
the replica-validity-factor
# is 10,
and
assuming a
default
repl-ping-replica-period of 10 seconds, the
# replica will not
try
to failover
if
it was not able to talk with the master
#
for
longer than 310 seconds.
#
# A large replica-validity-factor may allow replicas with too old data to failover
# a master,
while
a too small value may prevent the cluster from being able to
# elect a replica at all.
#
# For maximum availability, it is possible to set the replica-validity-factor
# to a value of 0, which means, that replicas will always
try
to failover the
# master regardless of the last time they interacted with the master.
# (However they'll always
try
to apply a delay proportional to their
# offset rank).
#
# Zero is the only value able to guarantee that when all the partitions heal
# the cluster will always be able to
continue
.
#
# cluster-replica-validity-factor 10
# Cluster replicas are able to migrate to orphaned masters, that are masters
# that are left without working replicas. This improves the cluster ability
# to resist to failures
as
otherwise an orphaned master can't be failed over
# in
case
of failure
if
it has no working replicas.
#
# Replicas migrate to orphaned masters only
if
there are still at least a
# given number of other working replicas
for
their old master. This number
# is the
"migration barrier"
. A migration barrier of 1 means that a replica
# will migrate only
if
there is at least 1 other working replica
for
its master
#
and
so forth. It usually reflects the number of replicas you want
for
every
# master in your cluster.
#
# Default is 1 (replicas migrate only
if
their masters remain with at least
# one replica). To disable migration just set it to a very large value.
# A value of 0 can be set but is useful only
for
debugging
and
dangerous
# in production.
#
# cluster-migration-barrier 1
# By
default
Redis Cluster nodes stop accepting queries
if
they detect there
# is at least an hash slot uncovered (no available node is serving it).
# This way
if
the cluster is partially down (
for
example a range of hash slots
# are no longer covered) all the cluster becomes, eventually, unavailable.
# It automatically returns available
as
soon
as
all the slots are covered again.
#
# However sometimes you want the subset of the cluster which is working,
# to
continue
to accept queries
for
the part of the key space that is still
# covered. In order to
do
so, just set the cluster-
require
-full-coverage
# option to no.
#
# cluster-
require
-full-coverage yes
# This option, when set to yes, prevents replicas from trying to failover its
# master during master failures. However the master can still perform a
# manual failover,
if
forced to
do
so.
#
# This is useful in different scenarios, especially in the
case
of multiple
# data center operations, where we want one side to never be promoted
if
not
# in the
case
of a total DC failure.
#
# cluster-replica-no-failover no
# In order to setup your cluster make sure to read the documentation
# available at http:
########################## CLUSTER DOCKER/NAT support ########################
# In certain deployments, Redis Cluster nodes address discovery fails, because
# addresses are NAT-ted
or
because ports are forwarded (the typical
case
is
# Docker
and
other containers).
#
# In order to make Redis Cluster working in such environments, a
static
# configuration where each node knows its
public
address is needed. The
# following two options are used
for
this scope,
and
are:
#
# * cluster-announce-ip
# * cluster-announce-port
# * cluster-announce-bus-port
#
# Each instruct the node about its address, client port,
and
cluster message
# bus port. The information is then published in the header of the bus packets
# so that other nodes will be able to correctly map the address of the node
# publishing the information.
#
# If the above options are not used, the normal Redis Cluster auto-detection
# will be used instead.
#
# Note that when remapped, the bus port may not be at the fixed offset of
# clients port + 10000, so you can specify any port
and
bus-port depending
# on how they get remapped. If the bus-port is not set, a fixed offset of
# 10000 will be used
as
usually.
#
# Example:
#
# cluster-announce-ip 10.1.1.5
# cluster-announce-port 6379
# cluster-announce-bus-port 6380
################################## 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 128
################################ LATENCY MONITOR ##############################
# The Redis latency monitoring subsystem samples different operations
# at runtime in order to collect data related to possible sources of
# latency of a Redis instance.
#
# Via the LATENCY command this information is available to the user that can
#
print
graphs
and
obtain reports.
#
# The system only logs operations that were performed in a time equal
or
# greater than the amount of milliseconds specified via the
# latency-monitor-threshold configuration directive. When its value is set
# to zero, the latency monitor is turned off.
#
# By
default
latency monitoring is disabled since it is mostly not needed
#
if
you don't have latency issues,
and
collecting data has a performance
# impact, that
while
very small, can be measured under big load. Latency
# monitoring can easily be enabled at runtime using the command
#
"CONFIG SET latency-monitor-threshold <milliseconds>"
if
needed.
latency-monitor-threshold 0
############################# EVENT NOTIFICATION ##############################
# Redis can notify Pub/Sub clients about events happening in the key space.
# This feature is documented at http:
#
# For instance
if
keyspace events notification is enabled,
and
a client
# performs a DEL operation on key
"foo"
stored in the Database 0, two
# messages will be published via Pub/Sub:
#
# PUBLISH __keyspace@0__:foo del
# PUBLISH __keyevent@0__:del foo
#
# It is possible to select the events that Redis will notify among a set
# of classes. Every
class
is identified by a single character:
#
# K Keyspace events, published with __keyspace@<db>__ prefix.
# E Keyevent events, published with __keyevent@<db>__ prefix.
# g Generic commands (non-type specific) like DEL, EXPIRE, RENAME, ...
# $ String commands
# l List commands
# s Set commands
# h Hash commands
# z Sorted set commands
# x Expired events (events generated every time a key expires)
# e Evicted events (events generated when a key is evicted
for
maxmemory)
# A Alias
for
g
$lshzxe
, so that the
"AKE"
string means all the events.
#
# The
"notify-keyspace-events"
takes
as
argument a string that is composed
# of zero
or
multiple characters. The
empty
string means that notifications
# are disabled.
#
# Example: to enable list
and
generic events, from the point of view of the
# event name,
use
:
#
# notify-keyspace-events Elg
#
# Example 2: to get the stream of the expired keys subscribing to channel
# name __keyevent@0__:expired
use
:
#
notify-keyspace-events Ex
#
# By
default
all notifications are disabled because most users don't need
# this feature
and
the feature has some overhead. Note that
if
you don't
# specify at least one of K
or
E, no events will be delivered.
#notify-keyspace-events
""
############################### ADVANCED CONFIG ###############################
# Hashes are encoded using a memory efficient data structure when they have a
# small number of entries,
and
the biggest entry does not exceed a given
# threshold. These thresholds can be configured using the following directives.
hash-max-ziplist-entries 512
hash-max-ziplist-value 64
# Lists are also encoded in a special way to save a lot of space.
# The number of entries allowed per internal list node can be specified
#
as
a fixed maximum size
or
a maximum number of elements.
# For a fixed maximum size,
use
-5 through -1, meaning:
# -5: max size: 64 Kb <-- not recommended
for
normal workloads
# -4: max size: 32 Kb <-- not recommended
# -3: max size: 16 Kb <-- probably not recommended
# -2: max size: 8 Kb <-- good
# -1: max size: 4 Kb <-- good
# Positive numbers mean store up to _exactly_ that number of elements
# per list node.
# The highest performing option is usually -2 (8 Kb size)
or
-1 (4 Kb size),
# but
if
your
use
case
is unique, adjust the settings
as
necessary.
list-max-ziplist-size -2
# Lists may also be compressed.
# Compress depth is the number of quicklist ziplist nodes from *each* side of
# the list to *exclude* from compression. The head
and
tail of the list
# are always uncompressed
for
fast push/pop operations. Settings are:
# 0: disable all list compression
# 1: depth 1 means "don't start compressing until after 1 node into the list,
# going from either the head
or
tail"
# So: [head]->node->node->...->node->[tail]
# [head], [tail] will always be uncompressed; inner nodes will compress.
# 2: [head]->[next]->node->node->...->node->[prev]->[tail]
# 2 here means: don't compress head
or
head->next
or
tail->prev
or
tail,
# but compress all nodes between them.
# 3: [head]->[next]->[next]->node->node->...->node->[prev]->[prev]->[tail]
# etc.
list-compress-depth 0
# Sets have a special encoding in just one
case
: when a set is composed
# of just strings that happen 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
# HyperLogLog sparse representation bytes limit. The limit includes the
# 16 bytes header. When an HyperLogLog using the sparse representation crosses
# this limit, it is converted into the dense representation.
#
# A value greater than 16000 is totally useless, since at that point the
# dense representation is more memory efficient.
#
# The suggested value is ~ 3000 in order to have the benefits of
# the space efficient encoding without slowing down too much PFADD,
# which is O(N) with the sparse encoding. The value can be raised to
# ~ 10000 when CPU is not a concern, but space is,
and
the data set is
# composed of many HyperLogLogs with cardinality in the 0 - 15000 range.
hll-sparse-max-bytes 3000
# Streams macro node max size / items. The stream data structure is a radix
# tree of big nodes that encode multiple items inside. Using this configuration
# it is possible to configure how big a single node can be in bytes,
and
the
# maximum number of items it may contain before switching to a
new
node when
# appending
new
stream entries. If any of the following settings are set to
# zero, the limit is ignored, so
for
instance it is possible to set just a
# max entires limit by setting max-bytes to 0
and
max-entries to the desired
# value.
stream-node-max-bytes 4096
stream-node-max-entries 100
# 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 a hash table
# that is rehashing, 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
# actively rehash 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 from time to time
# to queries with 2 milliseconds delay.
#
#
use
"activerehashing yes"
if
you don't have such hard requirements but
# want to free memory asap when possible.
activerehashing yes
# The client output buffer limits can be used to force disconnection of clients
# that are not reading data from the server fast enough
for
some reason (a
# common reason is that a Pub/Sub client can't consume messages
as
fast
as
the
# publisher can produce them).
#
# The limit can be set differently
for
the three different classes of clients:
#
# normal -> normal clients including MONITOR clients
# replica -> replica clients
# pubsub -> clients subscribed to at least one pubsub channel
or
pattern
#
# The syntax of every client-output-buffer-limit directive is the following:
#
# client-output-buffer-limit <
class
> <hard limit> <soft limit> <soft seconds>
#
# A client is immediately disconnected once the hard limit is reached,
or
if
# the soft limit is reached
and
remains reached
for
the specified number of
# seconds (continuously).
# So
for
instance
if
the hard limit is 32 megabytes
and
the soft limit is
# 16 megabytes / 10 seconds, the client will get disconnected immediately
#
if
the size of the output buffers reach 32 megabytes, but will also get
# disconnected
if
the client reaches 16 megabytes
and
continuously overcomes
# the limit
for
10 seconds.
#
# By
default
normal clients are not limited because they don't receive data
# without asking (in a push way), but just after a request, so only
# asynchronous clients may create a scenario where data is requested faster
# than it can read.
#
# Instead there is a
default
limit
for
pubsub
and
replica clients, since
# subscribers
and
replicas receive data in a push fashion.
#
# Both the hard
or
the soft limit can be disabled by setting them to zero.
client-output-buffer-limit normal 0 0 0
client-output-buffer-limit replica 256mb 64mb 60
client-output-buffer-limit pubsub 32mb 8mb 60
# Client query buffers accumulate
new
commands. They are limited to a fixed
# amount by
default
in order to avoid that a protocol desynchronization (
for
# instance due to a bug in the client) will lead to unbound memory usage in
# the query buffer. However you can configure it here
if
you have very special
# needs, such us huge multi/
exec
requests
or
alike.
#
# client-query-buffer-limit 1gb
# In the Redis protocol, bulk requests, that are, elements representing single
# strings, are normally limited ot 512 mb. However you can change this limit
# here.
#
# proto-max-bulk-len 512mb
# Redis calls an internal
function
to perform many background tasks, like
# closing connections of clients in timeout, purging expired keys that are
# never requested,
and
so forth.
#
# Not all tasks are performed with the same frequency, but Redis checks
for
# tasks to perform according to the specified
"hz"
value.
#
# By
default
"hz"
is set to 10. Raising the value will
use
more CPU when
# Redis is idle, but at the same time will make Redis more responsive when
# there are many keys expiring at the same time,
and
timeouts may be
# handled with more precision.
#
# The range is between 1
and
500, however a value over 100 is usually not
# a good idea. Most users should
use
the
default
of 10
and
raise this up to
# 100 only in environments where very low latency is required.
hz 10
# Normally it is useful to have an HZ value which is proportional to the
# number of clients connected. This is useful in order,
for
instance, to
# avoid too many clients are processed
for
each background task invocation
# in order to avoid latency spikes.
#
# Since the
default
HZ value by
default
is conservatively set to 10, Redis
# offers,
and
enables by
default
, the ability to
use
an adaptive HZ value
# which will temporary raise when there are many connected clients.
#
# When dynamic HZ is enabled, the actual configured HZ will be used
as
#
as
a baseline, but multiples of the configured HZ value will be actually
# used
as
needed once more clients are connected. In this way an idle
# instance will
use
very little CPU time
while
a busy instance will be
# more responsive.
dynamic-hz yes
# When a child rewrites the AOF file,
if
the following option is enabled
# the file will be fsync-ed every 32 MB of data generated. This is useful
# in order to commit the file to the disk more incrementally
and
avoid
# big latency spikes.
aof-rewrite-incremental-fsync yes
# When redis saves RDB file,
if
the following option is enabled
# the file will be fsync-ed every 32 MB of data generated. This is useful
# in order to commit the file to the disk more incrementally
and
avoid
# big latency spikes.
rdb-save-incremental-fsync yes
# Redis LFU eviction (see maxmemory setting) can be tuned. However it is a good
# idea to start with the
default
settings
and
only change them after investigating
# how to improve the performances
and
how the keys LFU change over time, which
# is possible to inspect via the OBJECT FREQ command.
#
# There are two tunable parameters in the Redis LFU implementation: the
# counter logarithm factor
and
the counter decay time. It is important to
# understand what the two parameters mean before changing them.
#
# The LFU counter is just 8 bits per key, it's maximum value is 255, so Redis
# uses a probabilistic increment with logarithmic behavior. Given the value
# of the old counter, when a key is accessed, the counter is incremented in
# this way:
#
# 1. A random number R between 0
and
1 is extracted.
# 2. A probability P is calculated
as
1/(old_value*lfu_log_factor+1).
# 3. The counter is incremented only
if
R < P.
#
# The
default
lfu-log-factor is 10. This is a table of how the frequency
# counter changes with a different number of accesses with different
# logarithmic factors:
#
# +--------+------------+------------+------------+------------+------------+
# | factor | 100 hits | 1000 hits | 100K hits | 1M hits | 10M hits |
# +--------+------------+------------+------------+------------+------------+
# | 0 | 104 | 255 | 255 | 255 | 255 |
# +--------+------------+------------+------------+------------+------------+
# | 1 | 18 | 49 | 255 | 255 | 255 |
# +--------+------------+------------+------------+------------+------------+
# | 10 | 10 | 18 | 142 | 255 | 255 |
# +--------+------------+------------+------------+------------+------------+
# | 100 | 8 | 11 | 49 | 143 | 255 |
# +--------+------------+------------+------------+------------+------------+
#
# NOTE: The above table was obtained by running the following commands:
#
# redis-benchmark -n 1000000 incr foo
# redis-cli object freq foo
#
# NOTE 2: The counter initial value is 5 in order to give
new
objects a chance
# to accumulate hits.
#
# The counter decay time is the time, in minutes, that must elapse in order
#
for
the key counter to be divided by two (
or
decremented
if
it has a value
# less <= 10).
#
# The
default
value
for
the lfu-decay-time is 1. A Special value of 0 means to
# decay the counter every time it happens to be scanned.
#
# lfu-log-factor 10
# lfu-decay-time 1
########################### ACTIVE DEFRAGMENTATION #######################
#
# WARNING THIS FEATURE IS EXPERIMENTAL. However it was stress tested
# even in production
and
manually tested by multiple engineers
for
some
# time.
#
# What is active defragmentation?
# -------------------------------
#
# Active (online) defragmentation allows a Redis server to compact the
# spaces left between small allocations
and
deallocations of data in memory,
# thus allowing to reclaim back memory.
#
# Fragmentation is a natural process that happens with every allocator (but
# less so with Jemalloc, fortunately)
and
certain workloads. Normally a server
# restart is needed in order to lower the fragmentation,
or
at least to
flush
# away all the data
and
create it again. However thanks to this feature
# implemented by Oran Agra
for
Redis 4.0 this process can happen at runtime
# in an
"hot"
way,
while
the server is running.
#
# Basically when the fragmentation is over a certain level (see the
# configuration options below) Redis will start to create
new
copies of the
# values in contiguous memory regions by exploiting certain specific Jemalloc
# features (in order to understand
if
an allocation is causing fragmentation
#
and
to allocate it in a better place),
and
at the same time, will release the
# old copies of the data. This process, repeated incrementally
for
all the keys
# will cause the fragmentation to drop back to normal values.
#
# Important things to understand:
#
# 1. This feature is disabled by
default
,
and
only works
if
you compiled Redis
# to
use
the
copy
of Jemalloc we ship with the source code of Redis.
# This is the
default
with Linux builds.
#
# 2. You never need to enable this feature
if
you don't have fragmentation
# issues.
#
# 3. Once you experience fragmentation, you can enable this feature when
# needed with the command
"CONFIG SET activedefrag yes"
.
#
# The configuration parameters are able to fine tune the behavior of the
# defragmentation process. If you are not sure about what they mean it is
# a good idea to leave the defaults untouched.
# Enabled active defragmentation
# activedefrag yes
# Minimum amount of fragmentation waste to start active defrag
# active-defrag-ignore-bytes 100mb
# Minimum percentage of fragmentation to start active defrag
# active-defrag-threshold-lower 10
# Maximum percentage of fragmentation at which we
use
maximum effort
# active-defrag-threshold-upper 100
# Minimal effort
for
defrag in CPU percentage
# active-defrag-cycle-min 5
# Maximal effort
for
defrag in CPU percentage
# active-defrag-cycle-max 75
# Maximum number of set/hash/zset/list fields that will be processed from
# the main dictionary scan
# active-defrag-max-scan-fields 1000