Redis as Cache in Distributed Network
I am new to Redis and little confused with the concept of Redis as Cache. I am developing one distributed application which will be running in 2 Data Centers have 2 servers per DC so total 4 servers will be running. Now I want to use Redis as cache so I am confused with the following question:-
To use Redis as cache do I have to install Redis on every( ie 4 ) servers so that all servers can locally access Redis? If I use 2 redis servers in master-slave mode for all the 4 servers can we call it a cache as every fetch will be on http call so I am not sure this will serve as cache. I understand that Redis as cache will be storing the data in memory but If the redis server is running on separate machine on network then will this still be called Cache is something which is confusing me?
It will be great if someone can clear this trivial concept for me.
A cache doesn't have to co-reside on the app server - it can be served over the network as long as it provides better latency than the source of truth that it fronts.