config.yaml

apiVersion: v1
kind: ConfigMap
metadata:
  name: redis-config
  labels:
    app: redis
data:
  redis.conf: |-
        # 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
        bind 0.0.0.0
        #
        # ~~~ 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 root123redis
        
        # 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 root123redis
        
        # 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://redis.io/topics/persistence for more information.
        
        appendonly yes
        
        # 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://antirez.com/post/redis-persistence-demystified.html
        #
        # 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://redis.io web site.
        
        ########################## 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://redis.io/topics/notifications
        #
        # 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