Picture storage with memcached or Redis

Recently in a picture class application, the reading speed of the picture is very high, generally from the physical hard disk reading speed does not reach expectations, so want to try memory storage, but hesitate to choose memcached or Redis, please help me analyze my idea is feasible, and should choose mem or Redis. My requirements are: 1, write operation is not much, mainly read operation, 2, do not have to consider the memory size problem, 3, permanent storage, the fault rate is low. Thank you

Reply to discussion (solution)

Memory picture?
The overhead of a picture is primarily the overhead of a network transmission.
It seems that you should choose a picture to store CDN instead of Redis,memcache.

Memory picture?
The overhead of a picture is primarily the overhead of a network transmission.
It seems that you should choose a picture to store CDN instead of Redis,memcache.
To explain, my application is to deal with the picture, a request about 20 or more of the graph to do processing, and finally generate a graph, so the cost in this piece and not on the transmission

Redis
1, the maximum capacity of the memcached is limited
2, memcached will not automatically save the content on the hard disk, does not meet the requirements of permanent storage

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