Debian11 系统优化脚本

一个自己使用的 Debian11 系统初始化脚本。
优化内容包括添加虚拟内存，使用 chrony 自动校时，设置时区为 Asia/Shanghai ，开启 BBR 以及一系列的内核参数调优。

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#!/bin/bash
echo '添加虚拟内存'
free -h
read -r -p "是否添加虚拟内存? [y/N] " add_swap
if [[ "$add_swap" =~ ^([yY][eE][sS]|[yY])$ ]]
then
echo '正在添加虚拟内存'
fallocate -l 2048M /swap
chmod 600 /swap
mkswap /swap
swapon /swap
echo '/swap none swap defaults 0 0' >> /etc/fstab
else
echo '取消添加虚拟内存'
fi
echo '正在更新系统'
apt-get update -y
apt-get upgrade -y
echo '正在安装依赖'
systemctl stop iptables
systemctl disable iptables
systemctl stop nftables
systemctl disable nftables
apt-get --purge autoremove iptables nftables -y
apt-get install chrony -y
echo '正在设置时区'
timedatectl set-timezone Asia/Shanghai
echo '启动自动校时'
/lib/systemd/systemd-sysv-install enable chrony
chronyc makestep
echo '优化系统配置'
modprobe ip_conntrack
cat > '/etc/sysctl.d/99-sysctl.conf' << EOF
net.ipv4.tcp_fack = 1
net.ipv4.tcp_early_retrans = 3
net.ipv4.neigh.default.unres_qlen=10000
net.ipv4.conf.all.route_localnet=1
net.ipv4.ip_forward = 1
net.ipv4.conf.all.forwarding = 1
net.ipv4.conf.default.forwarding = 1
net.ipv6.conf.all.forwarding = 1
net.ipv6.conf.default.forwarding = 1
net.ipv6.conf.lo.forwarding = 1
net.ipv6.conf.all.disable_ipv6 = 0
net.ipv6.conf.default.disable_ipv6 = 0
net.ipv6.conf.lo.disable_ipv6 = 0
net.ipv6.conf.all.accept_ra = 2
net.ipv6.conf.default.accept_ra = 2
net.core.netdev_max_backlog = 1000000
net.core.netdev_budget = 50000
net.core.netdev_budget_usecs = 5000
#fs.file-max = 51200
net.core.rmem_max = 67108864
net.core.wmem_max = 67108864
net.core.rmem_default = 67108864
net.core.wmem_default = 67108864
net.core.optmem_max = 65536
net.core.somaxconn = 1000000
net.ipv4.icmp_echo_ignore_all = 0
net.ipv4.icmp_echo_ignore_broadcasts = 1
net.ipv4.icmp_ignore_bogus_error_responses = 1
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.default.accept_redirects = 0
net.ipv4.conf.all.secure_redirects = 0
net.ipv4.conf.default.secure_redirects = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.all.rp_filter = 1
net.ipv4.tcp_keepalive_time = 600
net.ipv4.tcp_keepalive_intvl = 15
net.ipv4.tcp_keepalive_probes = 2
net.ipv4.tcp_synack_retries = 1
net.ipv4.tcp_syncookies = 0
net.ipv4.tcp_rfc1337 = 1
net.ipv4.tcp_timestamps = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_fin_timeout = 15
net.ipv4.ip_local_port_range = 1024 65535
net.ipv4.tcp_max_tw_buckets = 500000
net.ipv4.tcp_fastopen = 3
net.ipv4.tcp_rmem = 4096 87380 67108864
net.ipv4.tcp_wmem = 4096 65536 67108864
net.ipv4.udp_rmem_min = 8192
net.ipv4.udp_wmem_min = 8192
net.ipv4.tcp_mtu_probing = 1
net.ipv4.tcp_autocorking = 0
net.ipv4.tcp_slow_start_after_idle = 0
net.ipv4.tcp_max_syn_backlog = 819200
net.ipv4.tcp_notsent_lowat = 16384
net.ipv4.tcp_no_metrics_save = 0
net.ipv4.tcp_ecn = 2
net.ipv4.tcp_ecn_fallback = 1
net.ipv4.tcp_frto = 0
net.ipv6.conf.all.accept_redirects = 0
net.ipv6.conf.default.accept_redirects = 0
net.ipv4.neigh.default.gc_thresh3=8192
net.ipv4.neigh.default.gc_thresh2=4096
net.ipv4.neigh.default.gc_thresh1=2048
net.ipv6.neigh.default.gc_thresh3=8192
net.ipv6.neigh.default.gc_thresh2=4096
net.ipv6.neigh.default.gc_thresh1=2048
net.ipv4.tcp_orphan_retries = 1
net.ipv4.tcp_max_orphans = 100
net.ipv4.tcp_retries2 = 1
vm.swappiness = 1
vm.overcommit_memory = 1
kernel.pid_max=64000
net.netfilter.nf_conntrack_buckets = 262144
net.netfilter.nf_conntrack_max = 1000000
net.nf_conntrack_max = 1000000
net.netfilter.nf_conntrack_tcp_timeout_fin_wait = 60
net.netfilter.nf_conntrack_tcp_timeout_time_wait = 60
net.netfilter.nf_conntrack_tcp_timeout_close_wait = 30
net.netfilter.nf_conntrack_tcp_timeout_established = 600
net.core.default_qdisc = fq_pie
net.ipv4.tcp_congestion_control = bbr
fs.inotify.max_user_instances=8192
fs.inotify.max_user_watches=524288
EOF
sysctl -p
sysctl --system
echo always > /sys/kernel/mm/transparent_hugepage/enabled
cat > '/etc/systemd/system.conf' << EOF
[Manager]
#DefaultTimeoutStartSec=90s
DefaultTimeoutStopSec=3s
#DefaultRestartSec=100ms
DefaultLimitCORE=infinity
DefaultLimitNOFILE=infinity
DefaultLimitNPROC=infinity
DefaultTasksMax=infinity
EOF
cat > '/etc/security/limits.conf' << EOF
root soft nofile 1000000
root hard nofile 1000000
root soft nproc unlimited
root hard nproc unlimited
root soft core unlimited
root hard core unlimited
root hard memlock unlimited
root soft memlock unlimited

* soft nofile 1000000
* hard nofile 1000000
* soft nproc unlimited
* hard nproc unlimited
* soft core unlimited
* hard core unlimited
* hard memlock unlimited
* soft memlock unlimited
EOF
sed -i '/ulimit -SHn/d' /etc/profile
echo "ulimit -SHn 1000000" >> /etc/profile
if grep -q "pam_limits.so" /etc/pam.d/common-session
then
:
else
echo "session required pam_limits.so" >> /etc/pam.d/common-session
fi
systemctl daemon-reload
echo '重启系统生效'
reboot