Redis configuration file redis.conf description

Redis configuration file Parameter description:

1. Redis is not running as a daemon by default and can be modified by this configuration item, enabling the daemon with Yes
Daemonize No

2. When Redis is running as a daemon, Redis writes the PID to the/var/run/redis.pid file by default and can be specified by pidfile
Pidfile/var/run/redis.pid

3. Specify the Redis listening port, the default port is 6379, the author in his own article blog post explains why 6379 as the default port, because 6379 Merz the corresponding number on the phone keypad, and Merz from Italy showgirl Alessia Merz name
Port 6379

4. The host address of the binding
Bind 127.0.0.1

5. If the client closes the connection after a long period of inactivity, if it is specified as 0, the function is turned off
Timeout 300

6. Specify logging level, Redis supports four levels in total: Debug, verbose, notice, warning, default is verbose
LogLevel verbose

7. Logging mode, default to standard output, if Redis is configured to run as daemon, and this is configured as logging mode as 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 the Select command to specify the database ID on the connection
Databases 16

9. Specify how many times the update operation will synchronize the data to the data file and can be combined with multiple conditions
Save

There are three conditions available in the Redis default configuration file:
Save 900 1
Save 300 10
Save 60 10000
Represents 1 changes in 900 seconds (15 minutes), 5 changes in 300 seconds (10 minutes), and 60 changes in 10,000 seconds.

10. Specify whether to compress the data when storing to the local database, the default is Yes,redis with 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
Rdbcompression Yes

11. Specify the local database file name, the default value is Dump.rdb
Dbfilename Dump.rdb

12. Specify the local database to hold the directory
Dir./

13. Set the IP address and port of the master service when this machine is a Slav service, and it will automatically synchronize data from master when Redis boots
Slaveof

14. When the master service is password protected, the Slav service connects the password of master
Masterauth

15. Set the Redis connection password, if the connection password is configured, the client needs to provide the password via the auth command when connecting to Redis, which is turned off by default
Requirepass foobared

16. Set the maximum number of client connections at the same time, the default is unlimited, Redis can open the number of client connections for the Redis process can open the maximum number of file descriptors, if set maxclients 0, indicating no restrictions. 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 Redis memory limit, Redis will load data into memory when it is started, Redis will try to clear expired or expiring key first, when this method processing, still reach the maximum memory setting, will no longer write operation, but still can read operation. Redis new VM mechanism will store key memory, value will be stored in swap area
MaxMemory

18. Specifies whether logging occurs after each update operation, which, by default, writes data to disk asynchronously and, if not turned on, may result in data loss over a period of time when power is lost. Because the Redis itself synchronizes data files in sync with the save conditions above, some data will only exist in memory for a period of time. Default is No
AppendOnly No

19. Specify the update log file name, default to Appendonly.aof
Appendfilename appendonly.aof

20. Specify the update log condition, a total of 3 optional values:
No: Indicates that the data cache of the operating system is synchronized to disk (fast)
Always: Represents a manual call to Fsync () to write data to disk (slow, secure) after each update operation
Everysec: Indicates synchronization once per second (trade-offs, default values)

Appendfsync everysec

21. Specify whether to enable the virtual memory mechanism, the default value is no, a simple introduction, the VM mechanism to store data paging, by Redis will be less accessible pages, such as cold data swap to disk, Access to multiple pages is automatically swapped out into memory by the disk (in a later article I will carefully analyze the Redis VM mechanism)
Vm-enabled No

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

23. Store all data greater than vm-max-memory in virtual memory, regardless of the vm-max-memory settings, all index data is memory stored (REDIS index data is keys), that is, when the vm-max-memory is set to 0, In fact, all value is present on disk. The default value is 0
Vm-max-memory 0

The Redis swap file is divided into a number of page, an object can be saved on more than one page, but a page can not be shared by multiple objects, Vm-page-size is based on the size of the stored data to set, the author suggests that if you store many small objects, The page size is best set to 32 or 64bytes, and if you store large objects, you can use a larger page, and if you are unsure, use the default values
Vm-page-size 32

25. Set the number of pages in the swap file, since the page table (a bitmap that indicates that the page is idle or used) is in memory and consumes 1byte of memory per 8 pages on disk.
Vm-pages 134217728

26. Set the number of threads to access swap files, preferably do not exceed the machine's core number, if set to 0, then all the swap file operation is serial, may cause a relatively long delay. The default value is 4
Vm-max-threads 4

27. Set when replying to the client, whether to merge the smaller package into one package send, the default is to turn on
Glueoutputbuf Yes

28. Specifies that a special hashing algorithm is used when more than a certain number or maximum element exceeds a critical value
Hash-max-zipmap-entries 64
Hash-max-zipmap-value 512

29. Specify whether to activate the reset hash, which is on by default (described later in the introduction of the Redis hashing algorithm)
activerehashing Yes

30. Specify other profiles that can use the same configuration file across multiple Redis instances on the same host, while each instance has its own specific configuration file
Include/path/to/local.conf

31. Log Logging to Syslog
Syslog-enabled No

32. After configuring the Save parameter, after a storage count, the disk may be broken or permissions problems, the following parameter is set to Yes,redis will still work

Whether or not to continue working when persistent errors occur, whether to terminate all client write requests. The default setting "Yes" means termination, and once the snapshot data is saved, this server is read-only.

If "No", then this snapshot will fail, but the next snapshot will not be affected, but if there is a failure, the data can only be restored to "last success point"

Stop-writes-on-bgsave-error Yes

33. When the link from the master is removed from the host, if this value is yes, when the client queries from, the client responds, if it is the first synchronization will return a date data or this null value, if set to No, then return "SYNC with Master in progress" to info and Slaveof
Slave-serve-stale-data Yes

34. Read-only from server (default)
Slave-read-only Yes

35. The time interval (in seconds) from which pings are sent to the master
Repl-ping-slave-period 10

36. Batch transfer I/O timeout and master data or ping response timeout default 60s must be greater than Repl-ping-slave-period value
Repl-timeout 60

37. If this option is "yes" then Redis uses a smaller number of TCP packets and less bandwidth to send the data to, with a delay of 40 milliseconds (40 milliseconds in Linux kernel) from the host.

If no will reduce the delay in slave, but the traffic is used back relatively more, if more than one from the host, here is recommended to set to Yes
Repl-disable-tcp-nodelay No

38. From the host's priority, if when the master is hung up, it will pick one from the host as the master of the other slave, the lowest priority number will become the primary, 0 is a special level, and 0 will never be the master. The default value is 100.
Slave-priority 100

39. "Slow operation Log" record, in microseconds (one out of 10,000 seconds, 1000 * 1000), if the operation time exceeds this value, the command message will be "recorded" up. (Memory, non-file).

Where "Operation Time" does not include network IO expenses, only the time that the "Memory implementation" is requested after the server is reached. " 0 "means record all operations
Slowlog-log-slower-than 10000

40. The maximum number of bars retained by the slow operation log will be queued and the old record will be removed if this length is exceeded.

Slow record information can be viewed via "Slowlog args" (Slowlog get 10,slowlog Reset)
Slowlog-max-len 1000

Redis configuration file redis.conf description