RHEL/CentOS 在 6.3 版本以后引入了一套新的系统调优工具 tuned/tuned-adm，其中 tuned 是服务端程序，用来监控和收集系统各个组件的数据，并依据数据提供的信息动态调整系统设置，达到动态优化系统的目的;tuned-adm 是客户端程序，用来和 tuned 打交道，用命令行的方式管理和配置 tuned，tuned-adm 提供了一些预先配置的优化方案可供直接使用，比如：笔记本、虚拟机、存储服务器等。
如果你正在使用笔记本(电池电源)，想优化系统、节约电源又不想知道太多这方面的细节，就可以用 tuned/tuned-adm 这套工具并应用 laptop-battery-powersave 方案来调整和优化系统。当然不同的系统和应用场景有不同的优化方案，tuned-adm 预先配置的优化策略不是总能满足要求，这时候就需要定制，tuned-adm 允许用户自己创建和定制新的调优方案。
[root@1st-kvm tuned]# rpm -qa|grep tun
tuned-2.5.1-4.el7.noarch
[root@1st-kvm tuned]# less /var/log/tuned/tuned.log
[root@1st-kvm ~]# tuned-adm list
Available profiles:
- balanced
- desktop
- latency-performance
- network-latency
- network-throughput
- powersave
- throughput-performance
- virtual-guest
- virtual-host
Current active profile: balanced
[root@1st-kvm ~]# tuned-adm active
Current active profile: balanced
[root@1st-kvm ~]# tuned-adm profile virtual-host
[root@1st-kvm ~]# tuned-adm active
Current active profile: virtual-host
如果是企业存储服务器的话，可以用 enterprise-storage 方案：
tuned-adm profile enterprise-storage
上面预定的方案不是总能满足要求，如果有自己的需求可以定制自己的方案。自己定制很容易，切换到优化方案的配置目录，拷贝一个例子，然后编辑里面的相关参数就可以了，使用 tuned-adm list 命令会看到刚创建的新方案 my-virtual-host：
[root@1st-kvm tuned]# ll
total 16
drwxr-xr-x. 2 root root 23 Jul 24 14:59 balanced
drwxr-xr-x. 2 root root 23 Jul 24 14:59 desktop
-rw-r--r--. 1 root root 12260 May 19 2015 functions
drwxr-xr-x. 2 root root 23 Jul 24 14:59 latency-performance
drwxr-xr-x. 2 root root 23 Jul 24 14:59 network-latency
drwxr-xr-x. 2 root root 23 Jul 24 14:59 network-throughput
drwxr-xr-x. 2 root root 39 Jul 24 14:59 powersave
-rw-r--r--. 1 root root 1288 Aug 1 2015 recommend.conf
drwxr-xr-x. 2 root root 23 Jul 24 14:59 throughput-performance
drwxr-xr-x. 2 root root 23 Jul 24 14:59 virtual-guest
drwxr-xr-x. 2 root root 23 Jul 24 14:59 virtual-host
[root@1st-kvm tuned]# pwd
/usr/lib/tuned
在这个目录下，新建一个目录，修改里面的tuned.conf来配置参数，最后用tuned-adm active来选择这个定制的方案
[root@test tuned]# ls -R .: balanced desktop functions latency-performance network-latency network-throughput powersave recommend.d throughput-performance virtual-guest virtual-host ./balanced: tuned.conf ./desktop: tuned.conf ./latency-performance: tuned.conf ./network-latency: tuned.conf ./network-throughput: tuned.conf ./powersave: script.sh tuned.conf ./recommend.d: 50-tuned.conf ./throughput-performance: tuned.conf ./virtual-guest: tuned.conf ./virtual-host: tuned.conf [root@test tuned]# pwd /usr/lib/tuned
[root@test tuned]# cd network-throughput/ [root@test network-throughput]# cat tuned.conf # # tuned configuration # [main] summary=Optimize for streaming network throughput, generally only necessary on older CPUs or 40G+ networks include=throughput-performance [sysctl] # Increase kernel buffer size maximums. Currently this seems only necessary at 40Gb speeds. # # The buffer tuning values below do not account for any potential hugepage allocation. # Ensure that you do not oversubscribe system memory. net.ipv4.tcp_rmem="4096 87380 16777216" net.ipv4.tcp_wmem="4096 16384 16777216" net.ipv4.udp_mem="3145728 4194304 16777216"