系统调优

概述

内核参数、文件系统、网络优化技能。

内核参数调优

内存管理

bash

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bash

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/etc/sysctl.d/99-memory.conf

减少交换倾向

vm.swappiness = 10

脏页刷新

vm.dirty_ratio = 20 vm.dirty_background_ratio = 5

内存过量提交

vm.overcommit_memory = 1 vm.overcommit_ratio = 80

最大内存映射数

vm.max_map_count = 262144

应用

sysctl -p /etc/sysctl.d/99-memory.conf

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sysctl -p /etc/sysctl.d/99-memory.conf

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网络调优

bash

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/etc/sysctl.d/99-network.conf

TCP 缓冲区

net.core.rmem_max = 16777216 net.core.wmem_max = 16777216 net.ipv4.tcp_rmem = 4096 87380 16777216 net.ipv4.tcp_wmem = 4096 65536 16777216

连接队列

net.core.somaxconn = 65535 net.core.netdev_max_backlog = 65535 net.ipv4.tcp_max_syn_backlog = 65535

TIME_WAIT

net.ipv4.tcp_tw_reuse = 1 net.ipv4.tcp_fin_timeout = 30 net.ipv4.tcp_max_tw_buckets = 65535

端口范围

net.ipv4.ip_local_port_range = 1024 65535

Keep-Alive

net.ipv4.tcp_keepalive_time = 600 net.ipv4.tcp_keepalive_intvl = 30 net.ipv4.tcp_keepalive_probes = 3

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net.ipv4.tcp_keepalive_time = 600 net.ipv4.tcp_keepalive_intvl = 30 net.ipv4.tcp_keepalive_probes = 3

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文件系统

bash

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/etc/sysctl.d/99-fs.conf

文件句柄

fs.file-max = 2097152 fs.nr_open = 2097152

inotify

fs.inotify.max_user_watches = 524288 fs.inotify.max_user_instances = 512

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fs.inotify.max_user_watches = 524288 fs.inotify.max_user_instances = 512

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文件描述符限制

ulimit 配置

bash

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/etc/security/limits.conf

soft nofile 65535
hard nofile 65535
soft nproc 65535
hard nproc 65535

root soft nofile 65535 root hard nofile 65535

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soft nofile 65535
hard nofile 65535
soft nproc 65535
hard nproc 65535

root soft nofile 65535 root hard nofile 65535

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systemd 服务

bash

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/etc/systemd/system/myapp.service.d/limits.conf

[Service] LimitNOFILE=65535 LimitNPROC=65535

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[Service] LimitNOFILE=65535 LimitNPROC=65535

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磁盘 IO 调优

IO 调度器

bash

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bash

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查看当前调度器

cat /sys/block/sda/queue/scheduler

设置调度器

echo deadline > /sys/block/sda/queue/scheduler echo noop > /sys/block/sda/queue/scheduler # SSD echo mq-deadline > /sys/block/nvme0n1/queue/scheduler

永久设置 (GRUB)

GRUB_CMDLINE_LINUX="elevator=deadline"

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GRUB_CMDLINE_LINUX="elevator=deadline"

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预读设置

bash

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bash

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查看预读

blockdev --getra /dev/sda

设置预读 (KB)

blockdev --setra 4096 /dev/sda

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blockdev --setra 4096 /dev/sda

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挂载选项

bash

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/etc/fstab

SSD 优化

/dev/sda1 /data ext4 defaults,noatime,nodiratime,discard 0 2

数据库优化

/dev/sdb1 /mysql ext4 defaults,noatime,barrier=0 0 2

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/dev/sdb1 /mysql ext4 defaults,noatime,barrier=0 0 2

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CPU 调优

CPU 频率

bash

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bash

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查看调速器

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

设置性能模式

cpupower frequency-set -g performance

或直接设置

echo performance | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

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echo performance | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

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NUMA 优化

bash

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bash

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查看 NUMA 信息

numactl --hardware numastat

绑定 NUMA 节点

numactl --cpunodebind=0 --membind=0 ./program

查看进程 NUMA 分布

numastat -p PID

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numastat -p PID

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CPU 亲和性

bash

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bash

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查看亲和性

taskset -p PID

设置亲和性

taskset -c 0-3 ./program taskset -pc 0-3 PID

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taskset -c 0-3 ./program taskset -pc 0-3 PID

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常见场景

场景 1：Web 服务器优化

bash

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/etc/sysctl.d/99-web.conf

net.core.somaxconn = 65535 net.ipv4.tcp_max_syn_backlog = 65535 net.ipv4.tcp_tw_reuse = 1 net.ipv4.tcp_fin_timeout = 30 net.core.netdev_max_backlog = 65535

文件描述符

fs.file-max = 2097152

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fs.file-max = 2097152

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场景 2：数据库服务器优化

bash

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/etc/sysctl.d/99-database.conf

vm.swappiness = 1 vm.dirty_ratio = 40 vm.dirty_background_ratio = 10 vm.overcommit_memory = 1

大页内存

vm.nr_hugepages = 1024

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vm.nr_hugepages = 1024

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场景 3：高并发优化

bash

#!/bin/bash

bash

#!/bin/bash

一键优化脚本

网络

sysctl -w net.core.somaxconn=65535 sysctl -w net.ipv4.tcp_max_syn_backlog=65535 sysctl -w net.ipv4.ip_local_port_range="1024 65535"

文件

sysctl -w fs.file-max=2097152

内存

sysctl -w vm.swappiness=10

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sysctl -w vm.swappiness=10

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调优检查

项目	检查命令
文件限制	ulimit -n
网络参数	sysctl -a \| grep net
内存参数	sysctl -a \| grep vm
IO 调度	cat /sys/block/*/queue/scheduler

项目	检查命令
文件限制	ulimit -n
网络参数	sysctl -a \| grep net
内存参数	sysctl -a \| grep vm
IO 调度	cat /sys/block/*/queue/scheduler

故障排查

bash

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bash

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检查当前限制

cat /proc/PID/limits

检查打开文件数

ls /proc/PID/fd | wc -l lsof -p PID | wc -l

检查网络连接

ss -s netstat -an | awk '/tcp/ {print $6}' | sort | uniq -c

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ss -s netstat -an | awk '/tcp/ {print $6}' | sort | uniq -c

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tuning

Original

Translation

系统调优

系统调优

概述

概述

内核参数调优

内核参数调优

内存管理

内存管理

/etc/sysctl.d/99-memory.conf

/etc/sysctl.d/99-memory.conf

减少交换倾向

减少交换倾向

脏页刷新

脏页刷新

内存过量提交

内存过量提交

最大内存映射数

最大内存映射数

应用

应用

网络调优

网络调优

/etc/sysctl.d/99-network.conf

/etc/sysctl.d/99-network.conf

TCP 缓冲区

TCP 缓冲区

连接队列

连接队列

TIME_WAIT

TIME_WAIT

端口范围

端口范围

Keep-Alive

Keep-Alive

文件系统

文件系统

/etc/sysctl.d/99-fs.conf

/etc/sysctl.d/99-fs.conf

文件句柄

文件句柄

inotify

inotify

文件描述符限制

文件描述符限制

ulimit 配置

ulimit 配置

/etc/security/limits.conf

/etc/security/limits.conf

systemd 服务

systemd 服务

/etc/systemd/system/myapp.service.d/limits.conf

/etc/systemd/system/myapp.service.d/limits.conf

磁盘 IO 调优

磁盘 IO 调优

IO 调度器

IO 调度器

查看当前调度器

查看当前调度器

设置调度器

设置调度器

永久设置 (GRUB)

永久设置 (GRUB)

预读设置

预读设置

查看预读

查看预读

设置预读 (KB)

设置预读 (KB)

挂载选项

挂载选项

/etc/fstab

/etc/fstab

SSD 优化

SSD 优化

数据库优化

数据库优化

CPU 调优