Redis Vs Memcached

Comparison Index	Memcached	Redis
What is	Memcached is in-memory key-value store, originally intended for caching purpose.	Redis is in-memory data structure store, used as database, cache and message broker.
Description	MemcacheD is easy, simply designed yet powerful. Its simple design promotes fast deployment, ease of exaggeration, and solves many problems related to large data caches. It has its inbuilt APIs which provide a very large hash table distributed across multiple machines & uses internal memory management to provide more efficiency. MemcacheD supports only String data type which are ideal for storing read-only data. Memcached is a volatile in-memory key-value origin. It is multi-threaded and used primarily for caching objects.	Redis is an open source in-memory data structure store which also can be used as a database as well as caching. It supports almost all types of data structures such as strings, hashes, lists, sets, sorted sets with range queries, bitmaps, hyperloglogs and geospatial indexes through radius queries. Redis also can be used for messaging system used as pub/sub.
Primary database model	Memcached follows Key-value store database model.	Redis also follows Key-value store database model.
Developed By	Memcached is developed by Danga Interactive.	Redis is developed by Salvatore Sanfilippo.
Initial release	Memcached was initially released in 2003.	Redis was initially released in 2009.
Current release	Memcached current version is 1.5.1, released in August 2017.	Redis current version is 4.0.2, released in September 2017.
License	Memcached is free and open source.	Redis is also free and open source.
Cloud-based	No	No
Implementation language	Memcached is implemented in C language.	Redis is also implemented in C language.
Server operating systems	FreeBSD Linux OS X Unix Windows	BSD Linux OS X Windows
Supported programming languages	.Net, C, C++, ColdFusion, Erlang, Java, Lisp, Lua, OCaml, Perl, PHP, Python, Ruby	C,C#,C++, Clojure, Crystal, D, Dart, Elixir, Erlang, Fancy, Go, Haskell, Haxe, Java, JavaScript (Node.js), Lisp, Lua, MatLab, Objective-C, OCaml info, Perl, PHP, Prolog, Pure Data, Python, R, Rebol, Ruby, Rust, Scala, Scheme, Smalltalk, Tcl
Server-side scripts	No	Lua
Triggers	No	No
Partitioning methods	None	Sharding
Replication methods	None	Master-slave replication
MapReduce	No	No
Foreign keys	No	No
Transaction concepts	No	Optimistic locking, atomic execution of commands blocks and scripts
Concurrency	Yes	Yes
Durability	No	Yes
User concepts	Yes	Simple password-based access control
Installation	Memcached is little bit complicated to install and run.	Installing Redis is so much easier. No dependencies required.
Memory Usage	MemcacheD is more memory efficient than Redis because it consumes comparatively less memory resources for metadata.	Redis is more memory efficient, only after you use Redis hashes.
Persistence	Memcached doesn't use persistent data. While using Memcached, data might be lost with a restart and rebuilding cache is a costly process.	Redis can handle persistent data. By default it syncs data to the disk at least every 2 seconds, offering optional & tuneable data persistence meant to bootstrap the cache after a planned shutdown or an unintentional failure. While we tend to regard the data in caches as volatile and transient, persisting data to disk can be quite valuable in caching scenarios.
Replication	Memcached does not support replication.	Redis supports master-slave replication.
Storage type	MemcacheD stores variables in its memory and retrieves any information directly from the server memory instead of hitting the database again.	Redis is like a database that resides in memory. It executes (reads and writes) a key/value pair from its database to return the result set. That's why it is used by develepors for real-time metrics and analytics.
Execution Speed and Performance	MemcacheD is very good to handle high traffic websites. It can read many information at a time and give you back at a great response time.	Redis can neither handle high traffic on read nor heavy writes.
Data Structure	MemcacheD uses only strings and integers in its data structure. So, everything you save can either be a string or an integer. It is complicated because with integers, the only data manipulation you can do is adding or subtracting them. If you need to save arrays or objects, you will have to serialize them first and then save them. To read them back, you will need to un-serialize.	Redis has stronger data structures, which can handle not only strings integers but also binary-safe strings, lists of binary-safe strings, sets of binary-safe strings and sorted sets.
Key Length	Memcached's key length has a maximum of 250 bytes.	Redis' key-length has a maximum of 2GB.