Redis configuration file parameters

Redis does not run as a daemon by default. you can modify this configuration item and use yes to enable the daemon.

Configuration file parameters:

1. Redis does not run as a daemon by default. you can modify this configuration item and use yes to enable the daemon.

Daemonize no

2. when Redis runs as a daemon, Redis writes the pid to the/var/run/redis. pid file by default, which can be specified through pidfile

Pidfile/var/run/redis. pid

3. specify the Redis listening port. the default port is 6379. The author explains in his blog why 6379 is used as the default port, because 6379 corresponds to the MERZ number on the mobile phone key, MERZ is taken from the name of Alessia Merz, an Italian singer.

Port 6379

4. Bound host address

Bind 127.0.0.1

5. when the client is idle for a long time, the connection is closed. if it is set to 0, the function is disabled.

Timeout 300

6. specify the log record level. Redis supports four levels in total: debug, verbose, notice, and warning. the default value is verbose.

Loglevel verbose

7. log record mode. the default value is standard output. if Redis is configured to run in daemon mode and the log record mode is set to standard output, the log will be sent to/dev/null.

Logfile stdout

8. set the number of databases. the default database is 0. you can use SELECT Specifies the Database id on the connection.

Databases 16

9. specify how many update operations are performed within the specified time period to synchronize data to the data file. multiple conditions can be used together.

Save

The default configuration file of Redis provides three conditions:

Save 900 1

Save 300 10

Save 60 10000

1 Change in 900 seconds (15 minutes), 10 changes in 300 seconds (5 minutes), and 10000 changes in 60 seconds.

10. specify whether to compress data when stored in the local database. the default value is yes. Redis uses LZF to compress data. to save CPU time, disable this option, but this will cause huge changes in database files.

Rdbcompression yes

11. specify the local database file name. The default value is dump. rdb.

Dbfilename dump. rdb

12. specify the local database storage directory

Dir ./

13. set the IP address and port of the master service when the local machine is slav service. when Redis is started, it will automatically synchronize data from the master.

Slaveof

14. When password protection is set for the master service, the slav service connects to the master password

Masterauth

15. set the Redis connection password. if the connection password is configured, the client needs to use AUTH to connect to Redis. Password provided by the command, disabled by default

Requirepass foobared

16. set the maximum number of client connections at the same time. by default, there is no limit. the number of client connections that Redis can open at the same time is the maximum number of file descriptors that Redis processes can open. if you set maxclients 0, no limit is imposed. When the number of client connections reaches the limit, Redis closes the new connection and returns the max number of clients reached error message to the client.

Maxclients 128

17. specify the maximum memory limit of apsaradb for Redis. Redis loads data into the memory at startup. after the maximum memory is reached, Redis first tries to clear the expired or expiring Key, after this method is processed, it still reaches the maximum memory setting, and no write operation can be performed, but the read operation can still be performed. Redis's new vm mechanism stores keys in memory, and values in the swap area

Maxmemory

18. specify whether to record logs after each update operation. Redis asynchronously writes data to the disk by default. If this parameter is not enabled, data may be lost for a period of time during power failure. Because redis synchronizes data files according to the save conditions above, some data will only exist in the memory for a period of time. The default value is no.

Appendonly no

19. specify the update log file name. The default value is appendonly. aof.

Appendfilename appendonly. aof

20. specify the log update conditions. There are three optional values:
No: Indicates that the data cache is synchronized to the disk (fast) by the operating system)
Always: Indicates that fsync () is manually called after each update operation to write data to the disk (slow and secure)
Everysec: Indicates synchronization once per second (compromise, default value)

Appendfsync everysec

21. specifies whether to enable the virtual memory mechanism. the default value is no. for a brief introduction, the VM mechanism stores data on pages, and Redis stores cold data on the disk, that is, pages with less traffic, multiple accessed pages are automatically swapped out from the disk to the memory (I will carefully analyze the VM mechanism of Redis in the following article)

Vm-enabled no

22. Virtual memory file path. the default value is/tmp/redis. swap. it cannot be shared by multiple Redis instances.

Vm-swap-file/tmp/redis. swap

23. store all data greater than vm-max-memory into the virtual memory. no matter how small the vm-max-memory settings are, all Index data is stored in the memory (Redis's index data is keys ), that is to say, when vm-max-memory is set to 0, all values exist on the disk. The default value is 0.

Vm-max-memory 0

24. redis swap files are divided into many pages. one object can be stored on multiple pages, but one page cannot be shared by multiple objects, vm-page-size is set based on the size of stored data. The author suggests that if many small objects are stored, the page size should be set to 32 or 64 bytes. if a large object is stored, you can use a larger page. if you are not sure, use the default value.

Vm-page-size 32

25. set the number of pages in the swap file. because the page table (a bitmap indicating that the page is idle or used) is in the memory, every 8 pages on the disk consumes 1 byte of memory.

Vm-pages 134217728

26. set the number of threads used to access the swap file. it is best not to exceed the number of server cores. if it is set to 0, all operations on the swap file are serial, which may cause a long delay. The default value is 4.

Vm-max-threads 4

27. set whether to combine a small package into a package for sending when responding to the client. the function is enabled by default.

Glueoutputbuf yes

28. when a specified number or maximum element exceeds a critical value, a special hash algorithm is used.

Hash-max-zipmap-entries 64

Hash-max-zipmap-value 512

29. specify whether to enable or disable hash resetting. the default setting is enable (this will be detailed later when we introduce the hash algorithm of Redis)

Activerehashing yes

30. specify 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.

Include/path/to/local. conf