redis.conf AOF section comments improved.

[redis.git] / redis.conf

diff --git a/redis.conf b/redis.conf
index df23414c20af883c77a0b4ff9b0e7068564d72ba..bcad01e003f0217213d9449c57638a5b69957052 100644 (file)
--- a/redis.conf
+++ b/redis.conf
@@ -1,6 +1,6 @@
 # Redis configuration file example
 
 # Redis configuration file example
 

-# Note on units: when memory size is needed, it is possible to specifiy
+# 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
 # it in the usual form of 1k 5GB 4M and so forth:
 #
 # 1k => 1000 bytes


@@ -45,7 +45,7 @@ timeout 0
 # 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)
 # verbose (many rarely useful info, but not a mess like the debug level)
 # notice (moderately verbose, what you want in production probably)
 # warning (only very important / critical messages are logged)

-loglevel verbose
+loglevel notice

 
 # Specify the log file name. Also 'stdout' can be used to force
 # Redis to log on the standard output. Note that if you use standard
 
 # Specify the log file name. Also 'stdout' can be used to force
 # Redis to log on the standard output. Note that if you use standard


@@ -82,17 +82,47 @@ databases 16
 #   after 60 sec if at least 10000 keys changed
 #
 #   Note: you can disable saving at all commenting all the "save" lines.
 #   after 60 sec if at least 10000 keys changed
 #
 #   Note: you can disable saving at all commenting all the "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
 
 
 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 an hard way) that data is not persisting
+# on disk properly, otherwise chances are that no one will notice and some
+# distater 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 usually 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
 
 # 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 verison 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 filename where to dump the DB
 dbfilename dump.rdb
 


@@ -126,7 +156,7 @@ dir ./
 # is still in progress, the slave can act in two different ways:
 #
 # 1) if slave-serve-stale-data is set to 'yes' (the default) the slave will
 # is still in progress, the slave can act in two different ways:
 #
 # 1) if slave-serve-stale-data is set to 'yes' (the default) the slave will

-#    still reply to client requests, possibly with out of data data, or the
+#    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 slave-serve-stale data is set to 'no' the slave will reply with
 #    data set may just be empty if this is the first synchronization.
 #
 # 2) if slave-serve-stale data is set to 'no' the slave will reply with


@@ -135,6 +165,22 @@ dir ./
 #
 slave-serve-stale-data yes
 
 #
 slave-serve-stale-data yes
 

+# You can configure a slave instance to accept writes or not. Writing against
+# a slave instance may be useful to store some ephemeral data (because data
+# written on a slave 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 slaves are read-only.
+#
+# Note: read only slaves 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 slave exports by default all the administrative commands
+# such as CONFIG, DEBUG, and so forth. To a limited extend you can improve
+# security of read only slaves using 'rename-command' to shadow all the
+# administrative / dangerous commands.
+slave-read-only yes
+

 # Slaves send PINGs to server in a predefined interval. It's possible to change
 # this interval with the repl_ping_slave_period option. The default value is 10
 # seconds.
 # Slaves send PINGs to server in a predefined interval. It's possible to change
 # this interval with the repl_ping_slave_period option. The default value is 10
 # seconds.


@@ -167,7 +213,7 @@ slave-serve-stale-data yes
 
 # Command renaming.
 #
 
 # Command renaming.
 #

-# It is possilbe to change the name of dangerous commands in a shared
+# It is possible to change the name of dangerous commands in a shared

 # environment. For instance the CONFIG command may be renamed into something
 # of hard to guess so that it will be still available for internal-use
 # tools but not available for general clients.
 # environment. For instance the CONFIG command may be renamed into something
 # of hard to guess so that it will be still available for internal-use
 # tools but not available for general clients.


@@ -176,7 +222,7 @@ slave-serve-stale-data yes
 #
 # rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52
 #
 #
 # rename-command CONFIG b840fc02d524045429941cc15f59e41cb7be6c52
 #

-# It is also possilbe to completely kill a command renaming it into
+# It is also possible to completely kill a command renaming it into

 # an empty string:
 #
 # rename-command CONFIG ""
 # an empty string:
 #
 # rename-command CONFIG ""


@@ -195,21 +241,27 @@ slave-serve-stale-data yes
 # maxclients 10000
 
 # Don't use more memory than the specified amount of bytes.
 # maxclients 10000
 
 # Don't use more memory than the specified amount of bytes.

-# When the memory limit is reached Redis will try to remove keys with an
-# EXPIRE set. It will try to start freeing keys that are going to expire
-# in little time and preserve keys with a longer time to live.
-# Redis will also try to remove objects from free lists if possible.
-#
-# If all this fails, Redis will start to reply with errors to commands
-# that will use more memory, like SET, LPUSH, and so on, and will continue
-# to reply to most read-only commands like GET.
-#
-# WARNING: maxmemory can be a good idea mainly if you want to use Redis as a
-# 'state' server or cache, not as a real DB. When Redis is used as a real
-# database the memory usage will grow over the weeks, it will be obvious if
-# it is going to use too much memory in the long run, and you'll have the time
-# to upgrade. With maxmemory after the limit is reached you'll start to get
-# errors for write operations, and this may even lead to DB inconsistency.
+# When the memory limit is reached Redis will try to remove keys
+# accordingly to the eviction policy selected (see maxmemmory-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 cache, or to set
+# an hard memory limit for an instance (using the 'noeviction' policy).
+#
+# WARNING: If you have slaves attached to an instance with maxmemory on,
+# the size of the output buffers needed to feed the slaves 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 slaves 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 slaves attached it is suggested that you set a lower
+# limit for maxmemory so that there is some free RAM on the system for slave
+# output buffers (but this is not needed if the policy is 'noeviction').

 #
 # maxmemory <bytes>
 
 #
 # maxmemory <bytes>
 


@@ -219,7 +271,7 @@ slave-serve-stale-data yes
 # volatile-lru -> remove the key with an expire set using an LRU algorithm
 # allkeys-lru -> remove any key accordingly to the LRU algorithm
 # volatile-random -> remove a random key with an expire set
 # volatile-lru -> remove the key with an expire set using an LRU algorithm
 # allkeys-lru -> remove any key accordingly to the LRU algorithm
 # volatile-random -> remove a random key with an expire set

-# allkeys->random -> remove a random key, any key
+# allkeys-random -> remove a random key, any key

 # volatile-ttl -> remove the key with the nearest expire time (minor TTL)
 # noeviction -> don't expire at all, just return an error on write operations
 # 
 # volatile-ttl -> remove the key with the nearest expire time (minor TTL)
 # noeviction -> don't expire at all, just return an error on write operations
 # 


@@ -246,21 +298,23 @@ slave-serve-stale-data yes
 
 ############################## APPEND ONLY MODE ###############################
 
 
 ############################## APPEND ONLY MODE ###############################
 

-# By default Redis asynchronously dumps the dataset on disk. If you can live
-# with the idea that the latest records will be lost if something like a crash
-# happens this is the preferred way to run Redis. If instead you care a lot
-# about your data and don't want to that a single record can get lost you should
-# enable the append only mode: when this mode is enabled Redis will append
-# every write operation received in the file appendonly.aof. This file will
-# be read on startup in order to rebuild the full dataset in memory.
+# 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).

 #
 #

-# Note that you can have both the async dumps and the append only file if you
-# like (you have to comment the "save" statements above to disable the dumps).
-# Still if append only mode is enabled Redis will load the data from the
-# log file at startup ignoring the dump.rdb file.
+# 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.

 #
 #

-# IMPORTANT: Check the BGREWRITEAOF to check how to rewrite the append
-# log file in background when it gets too big.
+# 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://redis.io/topics/persistence for more information.

 
 appendonly no
 
 
 appendonly no
 


@@ -275,16 +329,19 @@ appendonly no
 #
 # 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.
 #
 # 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 if one second passed since the last fsync. Compromise.
+# everysec: fsync only one time every second. Compromise.

 #
 # The default is "everysec" that's usually the right compromise between
 # speed and data safety. It's up to you to understand if you can relax this to
 #
 # The default is "everysec" 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 will let the operating system flush the output buffer when
+# "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.
 #
 # 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://antirez.com/post/redis-persistence-demystified.html
+#

 # If unsure, use "everysec".
 
 # appendfsync always
 # If unsure, use "everysec".
 
 # appendfsync always


@@ -303,7 +360,7 @@ appendfsync everysec
 # BGSAVE or BGREWRITEAOF is in progress.
 #
 # This means that while another child is saving the durability of Redis is
 # BGSAVE or BGREWRITEAOF is in progress.
 #
 # This means that while another child is saving the durability of Redis is

-# the same as "appendfsync none", that in pratical terms means that it is
+# the same as "appendfsync none", that in practical terms means that it is

 # possible to lost up to 30 seconds of log in the worst scenario (with the
 # default Linux settings).
 # 
 # possible to lost up to 30 seconds of log in the worst scenario (with the
 # default Linux settings).
 # 


@@ -325,7 +382,7 @@ no-appendfsync-on-rewrite no
 # is useful to avoid rewriting the AOF file even if the percentage increase
 # is reached but it is still pretty small.
 #
 # is useful to avoid rewriting the AOF file even if the percentage increase
 # is reached but it is still pretty small.
 #

-# Specify a precentage of zero in order to disable the automatic AOF
+# Specify a percentage of zero in order to disable the automatic AOF

 # rewrite feature.
 
 auto-aof-rewrite-percentage 100
 # rewrite feature.
 
 auto-aof-rewrite-percentage 100


@@ -336,10 +393,10 @@ auto-aof-rewrite-min-size 64mb
 # Max execution time of a Lua script in milliseconds.
 #
 # If the maximum execution time is reached Redis will log that a script is
 # 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 maxium allowed time and will start to
+# still in execution after the maximum allowed time and will start to

 # reply to queries with an error.
 #
 # reply to queries with an error.
 #

-# When a long running script exceed the maxium execution time only the
+# When a long running script exceed 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 commands was
 # 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 commands was


@@ -349,25 +406,6 @@ auto-aof-rewrite-min-size 64mb
 # Set it to 0 or a negative value for unlimited execution without warnings.
 lua-time-limit 5000
 
 # 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 does not have
-# overlapping cluster configuration file names.
-#
-# cluster-config-file nodes-6379.conf
-
-# In order to setup your cluster make sure to read the documentation
-# available at http://redis.io web site.
-

 ################################## SLOW LOG ###################################
 
 # The Redis Slow Log is a system to log queries that exceeded a specified
 ################################## SLOW LOG ###################################
 
 # The Redis Slow Log is a system to log queries that exceeded a specified


@@ -394,12 +432,11 @@ slowlog-max-len 1024
 
 ############################### ADVANCED CONFIG ###############################
 
 
 ############################### ADVANCED CONFIG ###############################
 

-# Hashes are encoded in a special way (much more memory efficient) when they
-# have at max a given numer of elements, and the biggest element does not
-# exceed a given threshold. You can configure this limits with the following
-# configuration directives.
-hash-max-zipmap-entries 512
-hash-max-zipmap-value 64
+# 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

 
 # Similarly to hashes, small lists are also encoded in a special way in order
 # to save a lot of space. The special representation is only used when
 
 # Similarly to hashes, small lists are also encoded in a special way in order
 # to save a lot of space. The special representation is only used when


@@ -422,9 +459,9 @@ zset-max-ziplist-value 64
 
 # Active rehashing uses 1 millisecond every 100 milliseconds of CPU time in
 # order to help rehashing the main Redis hash table (the one mapping top-level
 
 # 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)
+# keys to values). The hash table implementation Redis uses (see dict.c)

 # performs a lazy rehashing: the more operation you run into an hash table
 # performs a lazy rehashing: the more operation you run into an hash table

-# that is rhashing, the more rehashing "steps" are performed, so if the
+# 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.
 # 
 # server is idle the rehashing is never complete and some more memory is used
 # by the hash table.
 # 


@@ -440,10 +477,47 @@ zset-max-ziplist-value 64
 # want to free memory asap when possible.
 activerehashing yes
 
 # 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
+# slave  -> slave clients and MONITOR clients
+# pubsub -> clients subcribed 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 slave clients, since
+# subscribers and slaves receive data in a push fashion.
+#
+# Both the hard or the soft limit can be disabled just setting it to zero.
+client-output-buffer-limit normal 0 0 0
+client-output-buffer-limit slave 256mb 64mb 60
+client-output-buffer-limit pubsub 32mb 8mb 60
+

 ################################## INCLUDES ###################################
 
 # Include one or more other config files here.  This is useful if you
 ################################## INCLUDES ###################################
 
 # Include one or more other config files here.  This is useful if you

-# have a standard template that goes to all redis server but also need
+# have a standard template that goes to all Redis server but also need

 # to customize a few per-server settings.  Include files can include
 # other files, so use this wisely.
 #
 # to customize a few per-server settings.  Include files can include
 # other files, so use this wisely.
 #