Conclusion It should be said that both memcached and Redis can meet our problems well, they are very high performance, in general, Redis can be understood as the expansion of memcached, is a more heavyweight implementation, providing more powerful features. Specifically: 1. Performance on: performance is excellent, specific to the details, because Redis only uses single core, and memcached can use multicore, So on average, Redis has a higher performance than memcached for storing small data on each core. In more than 100k of data, Memcached performance is higher than Redis, although Redis has recently been optimized for the performance of storing big data, but it is slightly inferior to memcached. 2. Memory space and data volume size: memcached can modify the maximum memory, using the LRU algorithm. Redis adds features to the VM, breaking the limits of physical memory. 3. Easy to operate:  MEMCACHED data structures are single and only used to cache data, and Redis supports richer data types, and can also be used directly on the server side to enrich the operation of the data. This reduces network IO times and data volumes. 4. Reliability on: memcached does not support data persistence, data loss after power outage or restart, but its stability is guaranteed. Redis supports data persistence and data recovery, allowing single points of failure, but also at the cost of performance. 5. Application Scenarios: memcached: Reduce database load, improve performance in dynamic system, cache, suitable for reading and writing, large data volume (such as Renren query user information, friend information, article information, etc.). redis: It is suitable for the high requirement of reading and writing efficiency, complicated data processing business and high security requirements (such as the count of Sina Weibo and the partial system of Weibo release, which are very high for data security and reading and writing requirements). Parts to be considered carefully 1.memcached a single key-value size is limited, and a value of only 1MB is supported, Redis's maximum supported 512mb2.memcached is just a memory cache, no requirement for reliability, and Redis prefers a memory database, so it is 3 more reliable. Essentially, memcached is just a single key-value memory cache;A data structure memory database, supporting five types of data, so redis, in addition to simple caching, can also handle some simple logic operations, Redis can not only cache, but also can be used as a database
4. The new version (3.0) of Redis refers to cluster distribution, that is, the cluster itself balanced client requests, each node can communicate, can expand the line, maintainability more powerful.
The difference between memcache and Redis
