Currently I have two servers which I have deployed node.js/Express.JS based web services API. I am using Redis for caching the JSON strings.
What will be the best option deploying this setup in to production? I see here it advices to go with a dedicated server redis. OK. I take it and use a dedicated server for running redis master. Can I use existing app servers as slave nodes? Note : these app servers are running an Node/Express application.
What other other options do I have?
You can.
It all depends on the load that those other servers have, it's a problem of resource sharing. To be honest my main issue with your architecture is not the dedicated vs the non-dedicated servers, it's the fact that you are placing a Redis server (master or not) on a host that most likely will be facing the internet (expressJS app), meaning, it's quite exposed.
If you can simulate HTTP load into your Node/Express JS servers, see the difference between running some benchmark tests on your dedicated server vs the non dedicated ones:
On a running redis server type in:
redis-benchmark -q -n 100000
If the app servers are being hammered and using all cores frequently you should see a substantial difference in the benchmarks.
My suggestion is, go ahead with your first setup and add monitoring for the redis response times, and only act when you have to, which might be now if the benchmarks show very poor results.
As a side note, consider the option of not sharing hosts for services that you expose to the internet with services that perform internal functions to your application.
来源：https://stackoverflow.com/questions/29131003/redis-deployment-configuration-master-slave-replication