都是根据自己实际情况选择，没有什么好与不好，所有的yum操作可能会因为网络跟解析问题失败，需要多试几次，都是可行的
1.增加history时间显示
vim /etc/bashrc最后追加
export HISTTIMEFORMAT="%Y-%m-%d %H:%M:%S "
export HISTSIZE=9999
2.ssh禁止DNS反解
vim /etc/ssh/sshd_config
UseDNS no
3.关火墙跟selinux
service iptables stop
chkconfig iptables off
iptables -F
service ip6tables stop
chkconfig ip6tables off
ip6tables -F
systemctl stop firewalld（7）
chkconfig firewalld off
vim /etc/sysconfig/selinux
selinux=disabled
4.yum源
这个其实自己有源镜像传上去用是最好的，但是可能只是想封装下一些常用软件进去所以想暂时指向下网络源，6.4的源163的用不了了我用的阿里的，剩下的应该没问题
sed -i s/gpgcheck=1/gpgcheck=0/g /etc/yum.repos.d/*
6.4阿里源repo，能联网直接复制就可用
# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client. You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the
# remarked out baseurl= line instead.
#
#
[base]
name=CentOS-$releasever - Base - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/os/$basearch/
http://mirrors.aliyuncs.com/centos/$releasever/os/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
gpgcheck=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-6
#released updates
[updates]
name=CentOS-$releasever - Updates - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/updates/$basearch/
http://mirrors.aliyuncs.com/centos/$releasever/updates/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
gpgcheck=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-6
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/extras/$basearch/
http://mirrors.aliyuncs.com/centos/$releasever/extras/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
gpgcheck=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-6
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/centosplus/$basearch/
http://mirrors.aliyuncs.com/centos/$releasever/centosplus/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
gpgcheck=0
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-6
#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/contrib/$basearch/
http://mirrors.aliyuncs.com/centos/$releasever/contrib/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib
gpgcheck=0
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-6
5.gcc
yum install gcc gcc-c++ -y（总会失败，因为解析的问题，多弄几次，这个是可以直接安装的）
6.sar
yum install sysstat -y（里面会带有sar）
7.nmon
去https://pkgs.org/search/?query=nmon&type=smart找自己对应版本的rpm扔上去直接rpm -ivh XXXX即可
8.安装中文字符集，重启后才有用
yum -y groupinstall chinese-support
vim /etc/sysconfig/i18n修改成
LANG="zh_CN.UTF-8"
SUPPORTED="zh_CN:zh:en_US.UTF-8:en_US:en:zh_CN.GB18030"
SYSFONT="latarcyrheb-sun16"
9.把语言切换成英语
localectl set-locale LANG=en_US.UTF-8