小内存VPS全能优化一键脚本 (ZRAM + 2GB Disk Swap + 内核调优)

VPS 极速优化脚本 (ZRAM + 2G Swap + 内核调优)
适用系统：Debian / Ubuntu / CentOS
使用方法：复制下方代码，保存为 optimize.sh，运行 sudo bash optimize.sh

#!/bin/bash

# ============================================================
# Description: Auto Setup ZRAM (Dynamic) + 2GB Disk Swap + Sysctl
# Author: Gemini Expert System
# ============================================================

# 检查 Root 权限
if [ "$(id -u)" != "0" ]; then
   echo "Error: 必须使用 root 运行此脚本" 1>&2
   exit 1
fi

echo ">> [1/5] 正在清理旧环境 (防止冲突)..."

# 1. 停止并移除现有的 ZRAM
if grep -q zram /proc/swaps; then
    swapoff /dev/zram0 2>/dev/null
    rmmod zram 2>/dev/null
fi
# 停止旧的服务
systemctl stop zram-config.service 2>/dev/null
systemctl disable zram-config.service 2>/dev/null
rm -f /etc/systemd/system/zram-config.service
rm -f /usr/local/bin/zram-start.sh

# 2. 停止并移除现有的磁盘 Swap
if grep -q '/swapfile' /proc/swaps; then
    swapoff /swapfile 2>/dev/null
fi
# 从 fstab 中彻底移除 swapfile 配置 (防止重复)
sed -i '/\/swapfile/d' /etc/fstab
# 删除物理文件
rm -rf /swapfile

echo ">> [2/5] 配置 ZRAM (内存压缩)..."

# 创建 ZRAM 启动脚本
cat << 'EOF' > /usr/local/bin/zram-start.sh
#!/bin/bash
modprobe zram num_devices=1
# 动态获取物理内存大小
total_mem=$(grep MemTotal /proc/meminfo | awk '{print $2}')
# 设置 ZRAM 大小为物理内存的 100% (1:1)
zram_size=${total_mem}K

# 优先选择 zstd 算法
algo="lzo"
if grep -q zstd /sys/block/zram0/comp_algorithm; then
    algo="zstd"
elif grep -q lz4 /sys/block/zram0/comp_algorithm; then
    algo="lz4"
fi

echo $algo > /sys/block/zram0/comp_algorithm
echo $zram_size > /sys/block/zram0/disksize
mkswap /dev/zram0 > /dev/null
# 优先级设为 100 (最高)
swapon --priority 100 /dev/zram0
echo "ZRAM Active: Algo=$algo, Size=$zram_size"
EOF

chmod +x /usr/local/bin/zram-start.sh

# 创建 Systemd 持久化服务
cat << EOF > /etc/systemd/system/zram-config.service
[Unit]
Description=Configure ZRAM for Low Memory VPS
After=multi-user.target

[Service]
Type=oneshot
ExecStart=/usr/local/bin/zram-start.sh
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target
EOF

systemctl daemon-reload
systemctl enable zram-config.service
systemctl restart zram-config.service

echo ">> [3/5] 创建 2GB 磁盘 Swap (保底保险)..."
# 创建 2048MB 文件
dd if=/dev/zero of=/swapfile bs=1M count=2048 status=progress
chmod 600 /swapfile
mkswap /swapfile
# 启用磁盘 swap，默认优先级 (-2)，让它排在 ZRAM 后面
swapon /swapfile
# 写入 fstab
echo '/swapfile none swap sw 0 0' >> /etc/fstab

echo ">> [4/5] 应用内核参数调优..."
cat << EOF > /etc/sysctl.d/99-vps-optimization.conf
# 积极使用 ZRAM (80)
vm.swappiness = 80
# 关闭 ZRAM 预读
vm.page-cluster = 0
# 保持文件系统缓存压力
vm.vfs_cache_pressure = 100
EOF
sysctl --system > /dev/null

echo ">> [5/5] ✅ 优化全部完成！状态检查："
echo "------------------------------------------------"
swapon --show
echo "------------------------------------------------"
free -h