I'm considering Redis backed web application, but I'm not sure about the hardware requirements for Redis, or really precisely how Redis "works"?

I'm new to Redis, as in... I'm really not sure how it works. But I'm considering it for a web app with a relatively uncomplicated data stru开发者_如何学Pythoncture that could benefit from Redis' speed. The thing is this app could end up getting millions and millions of rows. Since Redis is "in-memory" and "disk backed" does that mean I'm going to need enough memory to sport these millions of rows of values? Or does it only load values into memory that are recently or commonly accessed?

What sort of hardware requirements am I looking at? Does anyone have any real-world examples of Redis and hardware usage?

Redis handles memory in a great way. There are a few things to point out first. Redis will use less memory if compiled under a 32-bit system, but the maximum memory usage is 4GB. As for your hardware requirements, it all depends on why kind of data you are storing. If you are storing a million keys, but they only have a 8 character string inside it, the memory usage will be a lot lower than a 16 character string. The bottom line; If you are storing 1 million keys in memory, the ballpark memory usage might be around 1GB. I say might because there are a number of factors. Do you have virtual memory? Are all the keys access often? How big are the keys. There is a great post here that describes ways to improve redis memory usage

If you use the disk backend, then only the most frequently accessed keys will be stored in memory. You might have 1GB of data, but only 100Mb could be stored in memory. See here for more info

For hardware, lots of Ram.