To replicate, or not to replicate 1.Intro 

Hello, I am running web application on 2 separate geographical locations(e.g. Europe, Hong Kong). Let's suppose Hong Kong server is an Amazon EC2 instance(paying for disk space, IO disk operations and traffic). Inspect the following figure:



2.Problem

When you should remotely access DB server A and when you should add DB server B and replicate in between these 2 DB servers(MySQL master-master) ?

3.Additional questions

The cost of either approach can be easily calculated. I just need to "load test" the following variables for particular web application:

-replication traffic/db access traffic

-disk operations

-disk space

-num of users(load test)

Q: What's the best way to get the replication traffic ? Is there any good replication monitoring software or I should stick with wireshark, collectd ? 

Q: Are there any good blogs, papers, articles writing about similar topic ?

Thank you :)
Use maatkit heartbeat. You will need another perl process running is very helpful.

 You can also use mk-slave-delay to generate lag. Protection purposes.