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Today we will take a look at what the configuration items of Redis.conf do. If you want to use a tool well, the configuration content is the basis.
- daemonize no
Redis does not run as a daemon by default, it can be modified through this configuration item, and use yes to enable the daemon (Windows does not support the configuration of the daemon as no) - pidfile /var/run/redis.pid
When Redis is running as a daemon, Redis will write the pid to the /var/run/redis.pid file by default, which can be specified by pidfile - port 6379
specifies the Redis listening port. The default port is 6379. The author explained in a blog post why 6379 was selected as the default port, because 6379 is the number corresponding to MERZ on the phone button, and MERZ is taken from the name of the Italian singer Alessia Merz - bind 127.0.0.1
bind host address - timeout 300
When the client is idle for many seconds, the connection will be closed. If 0 is specified, the function will be closed - loglevel notice
specifies the logging level, Redis supports a total of four levels: debug, verbose, notice, warning, the default is notice - logfile stdout
logging mode, the default is standard output, if Redis is configured to run as a daemon, and the logging mode is configured as standard output here, the log will be sent to /dev/null (representing an empty device file, it etc. It is equivalent to just writing to a file, all the content written to it will be lost forever. Trying to read the content from it will not read anything.) - databases 16
set the number of databases, the default database is 0, you can use the SELECT command to specify the database id on the connection - save <seconds> <changes>
specifies how long and how many update operations to synchronize the data to the data file. Multiple conditions can be used in conjunction with the
Redis default configuration file. Three conditions are provided:
save 900 1 means 900 seconds 1 change in (15 minutes)
save 300 10 means 10 changes in 300 seconds (5 minutes)
save 60 10000 means 10000 changes in 60 seconds - rdbcompression yes
specifies whether to compress data when storing to the local database. The default is yes. Redis uses LZF compression. If you want to save CPU time, you can turn off this option, but it will cause the database file to become huge - dbfilename dump.rdb
specifies the name of the local database file, the default value is dump.rdb - dir ./
Specify the local database storage directory - slaveof <masterip> <masterport>
setting When this machine is the slave service, set the IP address and port of the master service. When Redis starts, it will automatically synchronize data from the master - masterauth <master-password>
When the master service is set to password protection, the password for the slave service to connect to the master - requirepass foobared
sets the Redis connection password. If the connection password is configured, the client needs to provide the password through the AUTH <password> command when connecting to Redis, which is closed by default - maxclients 128
sets the maximum number of client connections at the same time. The default is unlimited. The number of client connections that Redis can open at the same time is the maximum number of file descriptors that can be opened by the Redis process. If maxclients 0 is set, it means that there is no limit. When the number of client connections reaches the limit, Redis will close the new connection and return a max number of clients reached error message to the client - maxmemory <bytes>
Specify the maximum memory limit of Redis. Redis will load the data into the memory when it starts. After the maximum memory is reached, Redis will first try to clear the expired or expired keys. After this method is processed, it still reaches With the maximum memory setting, write operations can no longer be performed, but read operations can still be performed. Redis’s new vm mechanism will store Key in memory, and Value will be stored in the swap area - appendonly no
specifies whether to log after each update operation. Redis writes data to disk asynchronously by default. If it is not turned on, it may cause data loss for a period of time when the power is off. Because redis itself synchronizes data files according to the above save conditions, some data will only exist in memory for a period of time. The default is no - appendfilename appendonly.aof
specifies the name of the update log file, the default is appendonly.aof - appendfsync everysec
specifies the update log condition. There are 3 optional values:
no: means waiting for the operating system to synchronize data cache to disk (fast)
always: means manually calling fsync() after each update operation to write data to disk (slow, Security)
everysec: means sync once every second (compromise, default value) - vm-enabled no
specifies whether to enable the virtual memory mechanism. The default value is no. A brief introduction is that the VM mechanism stores data in pages. Redis will swap the less-visited pages, that is, cold data, to disk, and the more visited pages are from the disk. Automatically swap out to memory (I will carefully analyze Redis's VM mechanism in a later article) - vm-swap-file /tmp/redis.swap
virtual memory file path, the default value is /tmp/redis/swap, cannot be shared by multiple Redis instances - vm-max-memory 0
stores all data larger than vm-max-memory in virtual memory. No matter how small the vm-max-memory is set, all index data is stored in memory (Redis index data is keys), that is Say, when vm-max-memory is set to 0, all values actually exist on the disk. The default value is 0 - vm-page-size 32 The
Redis swap file is divided into many pages. An object can be stored on multiple pages, but one page cannot be shared by multiple objects. The vm-page-size should be set according to the size of the stored data. Certainly, the author suggests that if you store a lot of small objects, the page size is best set to 32 or 64bytes; if you store a lot of large objects, you can use a larger page, if you are not sure, use the default value - vm-pages 134217728
sets the number of pages in the swap file. Since the page table (a bitmap that indicates that the page is free or used) is placed in memory, every 8 pages on the disk will consume 1 byte of memory. - vm-max-threads 4
Set the number of threads accessing the swap file. It is best not to exceed the number of cores of the machine. If it is set to 0, then all operations on the swap file are serial, which may cause a longer delay. The default value is 4 - Glueoutputbuf yes
sets whether to combine smaller packages into one package and send when replying to the client, the default is on - hash-max-zipmap-entries 64 hash-max-zipmap-value 512
specifies that when a certain number or the largest element exceeds a certain critical value, a special hash algorithm is used - activerehashing yes
specifies whether to activate reset hashing, the default is on - include /path/to/local.conf
specifies to include other configuration files, you can use the same configuration file between multiple Redis instances on the same host, and each instance has its own specific configuration file
