Tune your CentOS 6.x system using tuned

tuned, a system performance tuning tool, comes with 9 different system tuning profiles for different scenarios. Each profile implements different tunables for different system resources such as cpu, network, ATA disk.  

tuned, normally runs as daemon and allows dynamic modification of system settings depending on usage.

Basically yo do:
# yum install tuned

#tuned-adm list

Available profiles:
- laptop-ac-powersave
- server-powersave
- laptop-battery-powersave
- desktop-powersave
- virtual-host
- virtual-guest
- enterprise-storage
- throughput-performance
- latency-performance
- spindown-disk
- default

# tuned-adm profile latency-performance

# to turn off:
#tuned-adm off

So, by running tuned, your system will always be optimally tuned.