Linux（centos）服务器环境通用优化

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建议服务器内存在8G或以上

1、内核参数优化

1）备份：

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cp /etc/sysctl.conf /etc/sysctl.conf.bak

2）添加内容：

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vi  /etc/sysctl.conf
#网络性能调优
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_mem = 131072  262144  524288
net.ipv4.tcp_rmem = 8760  256960  4088000
net.ipv4.tcp_wmem = 8760  256960  4088000

#TCP/IP调优参数
net.core.rmem_default = 256960
net.core.rmem_max = 513920
net.core.wmem_default = 256960
net.core.wmem_max = 513920
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_sack = 1
net.ipv4.tcp_window_scaling = 1

#常见内核参数调优
net.ipv4.tcp_fin_timeout = 30
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_keepalive_time = 1400
net.ipv4.ip_local_port_range = 9000    65000
net.ipv4.tcp_max_syn_backlog = 16384
net.ipv4.tcp_max_tw_buckets = 36000
net.ipv4.route.gc_timeout = 100
net.ipv4.tcp_keepalive_intvl = 30
net.ipv4.tcp_keepalive_probes = 3
net.ipv4.tcp_syn_retries = 1
net.ipv4.tcp_synack_retries = 1
net.core.somaxconn = 16384
net.core.netdev_max_backlog = 16384
net.ipv4.tcp_max_orphans = 16384
#内存单个段允许使用的大小，可以设置到总内存的90%
#例如16G内存16*1024*1024*1024*90%=15461882265
#shmall的大小可以是15461882265/4k(分页大小，getconf PAGESIZE可得到)= 3774873
#示例参数以8g内存作为标准
kernel.shmmax=7730941132
kernel.shmall=1887436
kernel.msgmax=65535
kernel.msgmnb=65535
#以下参数是对iptables防火墙的优化，防火墙不开会提示，可以忽略不理。
net.nf_conntrack_max = 25000000
net.netfilter.nf_conntrack_max = 25000000
net.netfilter.nf_conntrack_tcp_timeout_established = 180
net.netfilter.nf_conntrack_tcp_timeout_time_wait = 120
net.netfilter.nf_conntrack_tcp_timeout_close_wait = 60
net.netfilter.nf_conntrack_tcp_timeout_fin_wait = 120

3）生效配置：

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sysctl -p

2、关闭透明大页

目前已知mysql、oracle、redis内存大页功能会产生性能影响

在/etc/rc.local中增加如下内容

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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

3、调整客户端最大数

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vi /etc/security/limits.conf
* soft nofile 65536 # open files (-n)
* hard nofile 65536
* soft nproc 65565
* hard nproc 65565 # max user processes (-u)

4、关闭selinux

修改/etc/selinux/config文件中设置

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SELINUX=disabled

5、关闭防火墙

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systemctl stop firewalld.service     #停止firewall
systemctl disable firewalld.service  #禁止firewall开机启动

6、禁用交换区

可以执行如下命令:

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Swapoff -a

7、修改mysql配置文件

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[mysqld]
server_id=1
transaction_isolation=READ-COMMITTED
character_set_server=utf8mb4
collation_server=utf8mb4_unicode_ci
log_bin=db-binlog
binlog_format=mixed
expire_logs_days=15
max_connections=200
join_buffer_size=4M
sort_buffer_size=4M
read_rnd_buffer_size=16M
innodb_log_buffer_size=16M
innodb_buffer_pool_size=【物理内存*（0.5~0.75）】
innodb_log_file_size=256M

[client]
default-character-set=utf8mb4