cubicdaiya/neoagent — Issue #12: improve ability of checking health of server
Author: cubicdaiya
Created: 2012-03-05 16:13:01+00:00
State: open

neoagent has a function of 'health check'. But this checks whether connecting a target server with the system call of `connect`.
This method is not very good at all. when a target server is down this behaves efficiently, this doesn't in other case.(for example, a target server is too busy because of overload with many disk I/Os)

A new method of 'health check' uses memcached commands(get & set).
A health checker executes multiple set commands, then executes get commands corresponding to each set command.
A health checker switches server when all set and get commands fail.