centos 7.x 的一些系统层面设置详解程序员

安装数据库经常做一些os的设置，简单总结一下，随时补充

rc.local

# vi /etc/rc.local 
 
############################################ 
#disable transparent hugepage 
############################################ 
if test -f /sys/kernel/mm/transparent_hugepage/enabled; then 
   echo never > /sys/kernel/mm/transparent_hugepage/enabled 
fi 
if test -f /sys/kernel/mm/transparent_hugepage/defrag; then 
   echo never > /sys/kernel/mm/transparent_hugepage/defrag 
fi 
 
############################################ 
#set read block size 
############################################ 
blockdev --setra 16384 /dev/sda 
 
############################################ 
#set io scheduler to deadline for every disk 
############################################ 
echo deadline > /sys/block/sda/queue/scheduler 
 
############################################ 
#set write type  
# 0:write through 
# 1:write back 
# hdparm -I /dev/sda |grep "Write cache" 
# hdparm -W 0 /dev/sda 
# hdparm -W 1 /dev/sda 
############################################ 
hdparm -W 0 /dev/sda  
 
 

grant exec

# chmod u+x /etc/rc.d/rc.local

sysctl.conf

# vi /etc/sysctl.conf 
 
kernel.shmall = 18446744073692774399     
kernel.shmmax = 18446744073692774399     
kernel.shmmni = 819200  
 
kernel.sem = 4096 2147483647 2147483646 512000  
 
net.core.rmem_default = 262144     
net.core.rmem_max = 4194304     
net.core.wmem_default = 262144     
net.core.wmem_max = 4194304  
 
net.ipv4.tcp_rmem=8192 87380 16777216     
net.ipv4.tcp_wmem=8192 65536 16777216   
 
net.ipv4.tcp_keepalive_intvl=20     
net.ipv4.tcp_keepalive_probes=3     
net.ipv4.tcp_keepalive_time=60  
 
net.ipv4.tcp_mem=8388608 12582912 16777216   
net.ipv4.ip_local_port_range=10000 65535   
 
vm.dirty_background_bytes = xxxx000000     
vm.dirty_expire_centisecs = 6000     
vm.dirty_ratio = 80     
vm.dirty_writeback_centisecs = 50 
 
vm.overcommit_memory = 2 
vm.overcommit_ratio = 90 
vm.swappiness = 1 
 
vm.nr_hugepages = xxxx 
 
fs.nr_open=20480000 
fs.file-max=7672460 
fs.aio-max-nr=1048576

生效

# sysctl -p 
# sysctl -a

resource limit

# vi /etc/security/limits.conf 
 
root soft nofile  655360 # The maximum number of open file descriptors 
root hard nofile  655360 
 
root soft nproc   655360 # The maximum number of processes available to a single user 
root hard nproc   655360 
 
* soft memlock unlimited # The maximum size that may be locked into memory 
* hard memlock unlimited 
 
* soft core    unlimited # The maximum size of core files created 
* hard core    unlimited 
 
* soft stack   unlimited   
* hard stack   unlimited  
 

disable selinux

# vi /etc/selinux/config 
SELINUX=DISABLED

disable firewalld

# systemctl stop firewalld.service 
# systemctl disable firewalld.service

disable ipv6

# vi /etc/default/grub 
ipv6.disable=1

disable numa

# vi /etc/default/grub 
numa=off 

disable transparent hugepage

# vi /etc/default/grub 
transparent_hugepage=never 

set all disk ioscheduler

# vi /etc/default/grub 
elevator=deadline

new grub

# grub2-mkconfig -o /boot/grub2/grub.cfg