Redis配置檔案（1）units/includes/GENERAL/SECURITY/LIMITS

redis.conf檔案

在Linux進行檔案的檢視！

units單位：

8 # Note on units: when memory size is needed, it is possible to specify
9 # it in the usual form of 1k 5GB 4M and so forth:
10 #
11 # 1k => 1000 bytes
12 # 1kb => 1024 bytes
13 # 1m => 1000000 bytes
14 # 1mb => 1024*1024 bytes
15 # 1g => 1000000000 bytes
16 # 1gb => 1024*1024*1024 bytes
17 #
18 # units are case insensitive so 1GB 1Gb 1gB are all the same.

1  配置大小單位,開頭定義了一些基本的度量單位，只支援bytes，不支援bit

2  對大小寫不敏感

includes：

20 ################################## INCLUDES ##############################
22 # Include one or more other config files here.This is useful if you
23 # have a standard template that goes to all Redis servers but also need
24 # to customize a few per-server settings.Include files can include
25 # other files, so use this wisely.
26 #
27 # Notice option "include" won't be rewritten by command "CONFIG REWRITE"
28 # from admin or Redis Sentinel. Since Redis always uses the last processed
29 # line as value of a configuration directive, you'd better put includes
30 # at the beginning of this file to avoid overwriting config change at runtime.
31 #
32 # If instead you are interested in using includes to override configuration
33 # options, it is better to use include as the last line.
34 #
35 # include /path/to/local.conf

GENERAL

141 # If a pid file is specified, Redis writes it where specified at startup
142 # and removes it at exit.
143 #
144 # When the server runs non daemonized, no pid file is created if none is
145 # specified in the configuration. When the server is daemonized, the pid file
146 # is used even if not specified, defaulting to "/var/run/redis.pid".
147 #
148 # Creating a pid file is best effort: if Redis is not able to create it
149 # nothing bad happens, the server will start and run normally.
150 pidfile /var/run/redis_6379.pid

126 # By default Redis does not run as a daemon. Use 'yes' if you need it.
127 # Note that Redis will write a pid file in /var/run/redis.pid when daemonized.
128 daemonize yes

82 # Accept connections on the specified port, default is 6379 (IANA #815344).
83 # If port 0 is specified Redis will not listen on a TCP socket.
84 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

tcp-backlog
設定tcp的backlog，backlog其實是一個連線佇列，backlog佇列總和=未完成三次握手佇列 + 已經完成三次握手佇列。
在高併發環境下你需要一個高backlog值來避免慢客戶端連線問題。注意Linux核心會將這個值減小到
/proc/sys/net/core/somaxconn的值，所以需要確認增大somaxconn和tcp_max_syn_backlog兩個值
來達到想要的效果

# Close the connection after a client is idle for N seconds (0 to disable)
timeout 0

# IF YOU ARE SURE YOU WANT YOUR INSTANCE TO LISTEN TO ALL THE INTERFACES
# JUST COMMENT THE FOLLOWING LINE.
# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
bind 127.0.0.1

# 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
單位為秒，如果設定為0，則不會進行Keepalive檢測，建議設定成60

# 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
日誌級別

# 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 ""
日誌的名字

# 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
系統預設的庫16個
預設使用0庫

# 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是否把日誌輸出到syslog中
系統日誌預設時關著
# Specify the syslog identity.
# syslog-ident redis指定syslog裡的日誌標誌
裝置以redis開頭
# Specify the syslog facility. Must be USER or between LOCAL0-LOCAL7.
# syslog-facility local0
指定syslog裝置，值可以是USER或LOCAL0-LOCAL7
預設使用local0

SECURITY安全

訪問密碼的檢視、設定和取消

設定密碼：

config set requirepass " "

;

改為空的時候預設沒有密碼！

467 ################################## SECURITY ###################################
468
469 # Require clients to issue AUTH <PASSWORD> before processing any other
470 # commands.This might be useful in environments in which you do not trust
471 # others with access to the host running redis-server.

要求必須auth + password 在任何命令之前

Redis一般做的是快取，不是安全，而且系統會認為Linux是在安全的環境下....

LIMITS限制

maxclients:

設定redis同時可以與多少個客戶端進行連線。預設情況下為10000個客戶端。當你
無法設定程序檔案控制代碼限制時，redis會設定為當前的檔案控制代碼限制值減去32，因為redis會為自
身內部處理邏輯留一些控制代碼出來。如果達到了此限制，redis則會拒絕新的連線請求，並且向這
些連線請求方發出“max number of clients reached”以作迴應。


509 # Once the limit is reached Redis will close all the new connections sending
510 # an error 'max number of clients reached'.
511 #
512 # maxclients 10000
預設情況下為10000個客戶端

maxmemory

設定redis可以使用的記憶體量。一旦到達記憶體使用上限，redis將會試圖移除內部資料，移除規則可以通過maxmemory-policy來指定。
如果redis無法根據移除規則來移除記憶體中的資料，或者設定了“不允許移除”，
那麼redis則會針對那些需要申請記憶體的指令返回錯誤資訊，比如SET、LPUSH等。
但是對於無記憶體申請的指令，仍然會正常響應，比如GET等。如果你的redis是主redis（說明你的redis有從redis），
那麼在設定記憶體使用上限時，需要在系統中留出一些記憶體空間給同步佇列快取，只有在你設定的是“不移除”的情況下，才不用考慮這個因素


533 # In short... if you have slaves attached it is suggested that you set a lower
534 # limit for maxmemory so that there is some free RAM on the system for slave
535 # output buffers (but this is not needed if the policy is 'noeviction').
537 # maxmemory <bytes>

maxmemory-policy:

最大快取清楚策略

（1）volatile-lru：使用LRU演算法移除key，只對設定了過期時間的鍵
（2）allkeys-lru：使用LRU演算法移除key
（3）volatile-random：在過期集合中移除隨機的key，只對設定了過期時間的鍵
（4）allkeys-random：移除隨機的key
（5）volatile-ttl：移除那些TTL值最小的key，即那些最近要過期的key
（6）noeviction：不進行移除。針對寫操作，只是返回錯誤資訊
LRU 演算法或者 TTL 演算法都是不是很精確演算法，而是 個近似演算法。


539 # MAXMEMORY POLICY: how Redis will select what to remove when maxmemory
540 # is reached. You can select among five behaviors:
541 #
542 # volatile-lru -> remove the key with an expire set using an LRU algorithm
543 # allkeys-lru -> remove any key according to the LRU algorithm
544 # volatile-random -> remove a random key with an expire set
545 # allkeys-random -> remove a random key, any key
546 # volatile-ttl -> remove the key with the nearest expire time (minor TTL)
547 # noeviction -> don't expire at all, just return an error on write operations

maxmemory-samples

設定樣本數量，LRU演算法和最小TTL演算法都並非是精確的演算法，而是估算值，所以你可以設定樣本的大小，
redis預設會檢查這麼多個key並選擇其中LRU的那個


562 # LRU and minimal TTL algorithms are not precise algorithms but approximated
563 # algorithms (in order to save memory), so you can tune it for speed or
564 # accuracy. For default Redis will check five keys and pick the one that was
565 # used less recently, you can change the sample size using the following
566 # configuration directive.
568 # The default of 5 produces good enough results. 10 Approximates very closely
569 # true LRU but costs a bit more CPU. 3 is very fast but not very accurate.
571 # maxmemory-samples 5