Tuning a RHEL system for optimum application performance isn't simple. One feature of RHEL6 that is under-used to this end is tuned. Although this deamon is capable of reacting to changes in system resources (like CPU utilization), one simple feature that would benefit many deployments is the tuned profile.
You can use profiles to make kernel tuning persistent in a way that is more in-line with enterprise expectations (i.e. It's much better than rc.local scripts), and you can use them for common application deployments (like webservers, email servers, file servers, and database servers)
Various tuned profiles are available on RHEL6 and you can find them documented here: https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/6/html-single/Performance_Tuning_Guide/index.html#main-analyzeperf-tuned
Does anyone here use tuned profiles in their environment? If you do, please share it here, along with the version of RHEL you're using and the application/workload it's used for.