The Redis storage is divided into memory storage, disk storage, and log files, which are configured with three parameters in the configuration file.
Save seconds Updates,save Configuration, indicates how many times the update operation has been synchronized to the data file. This can be a combination of multiple conditions, such as the default configuration file settings, set three conditions.
appendonly Yes/no ,appendonly configuration, indicates whether logging occurs after each update operation 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.
Appendfsync no/always/everysec ,appendfsync configuration,no Indicates that the data cache is synchronized to disk by the operating system, always means that the data is written to disk by manually calling Fsync() After each update operation, andeverysec means synchronizing once per second.
See also: http://www.cnblogs.com/shanyou/archive/2012/01/28/2330451.html
Using "Sentinel" mechanism to monitor the master-slave server for automatic switching
Redis Persistence mode