云主机Nginx反向代理到IIS服务器502？IIS应用程序池回收

# 通过PowerShell禁用基于时间的自动回收（保留内存和请求数触发）  
Import-Module WebAdministration  

# 获取应用程序池名称  
$appPoolName = "DefaultAppPool"  

# 修改回收设置  
Set-ItemProperty "IIS:\AppPools\$appPoolName" -Name "Recycling.periodicRestart.time" -Value "00:00:00"  
Set-ItemProperty "IIS:\AppPools\$appPoolName" -Name "Recycling.periodicRestart.memory" -Value 1024  # 1GB内存限制  
Set-ItemProperty "IIS:\AppPools\$appPoolName" -Name "Recycling.periodicRestart.privateMemory" -Value 2048  # 2GB私有内存限制  
Set-ItemProperty "IIS:\AppPools\$appPoolName" -Name "Recycling.periodicRestart.requests" -Value 5000  # 5000个请求后回收  

根据服务器内存配置动态调整：  
- 32GB内存服务器：privateMemory=8192 (8GB)  
- 64GB内存服务器：privateMemory=16384 (16GB)  
- 128GB内存服务器：privateMemory=32768 (32GB)  

# 防止强制终止超时进程（延长关闭超时时间）  
Set-ItemProperty "IIS:\AppPools\$appPoolName" -Name "ProcessModel.shutdownTimeLimit" -Value "00:01:30"  # 90秒  
Set-ItemProperty "IIS:\AppPools\$appPoolName" -Name "ProcessModel.startupTimeLimit" -Value "00:01:00"   # 60秒  

# 启用重叠回收（减少请求中断）  
Set-ItemProperty "IIS:\AppPools\$appPoolName" -Name "Recycling.disallowOverlappingRotation" -Value $false  
Set-ItemProperty "IIS:\AppPools\$appPoolName" -Name "Recycling.logEventOnRecycle" -Value "Time, Memory, PrivateMemory, Requests"  

# 保存为C:\Scripts\Monitor-IISAppPool.ps1  
$appPoolName = "DefaultAppPool"  
$memoryLimit = 2048  # MB  
$requestLimit = 5000  

$appPool = Get-Item "IIS:\AppPools\$appPoolName"  
$currentMemory = $appPool.workerProcesses.currentMemoryUsage / 1MB  
$currentRequests = $appPool.workerProcesses.currentRequests  

Write-Output "$(Get-Date -Format 'yyyy-MM-dd HH:mm:ss'): AppPool '$appPoolName' - Memory: $currentMemory MB / $memoryLimit MB, Requests: $currentRequests / $requestLimit"  

if ($currentMemory -gt $memoryLimit * 0.9) {  
    Write-Output "WARNING: Memory usage exceeds 90% of limit"  
    # Send-MailMessage -To "admin@example.com" -Subject "IIS AppPool Memory Alert" -Body "Memory usage exceeds 90% of limit" -SmtpServer "smtp.example.com"  
}  

if ($currentRequests -gt $requestLimit * 0.9) {  
    Write-Output "WARNING: Request count exceeds 90% of limit"  
}  

# 每5分钟运行一次  
$action = New-ScheduledTaskAction -Execute "PowerShell.exe" -Argument "-File C:\Scripts\Monitor-IISAppPool.ps1"  
$trigger = New-ScheduledTaskTrigger -Minutes 5  
Register-ScheduledTask -TaskName "MonitorIISAppPool" -Action $action -Trigger $trigger -RunLevel Highest  

upstream iis_backend {  
  server 127.0.0.1:8080 fail_timeout=0;  # IIS本地监听端口  
  keepalive 32;  # 保持长连接数（建议为IIS最大工作进程数的2倍）  
}  

server {  
  listen 80;  
  server_name example.com;  

  location / {  
    proxy_pass http://iis_backend;  
    proxy_set_header Host $host;  
    proxy_set_header X-Real-IP $remote_addr;  
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;  

    # 超时设置（需与IIS回收时间协同）  
    proxy_connect_timeout 10s;  
    proxy_send_timeout 120s;    # 适配文件上传等耗时操作  
    proxy_read_timeout 120s;  

    # 缓冲区优化（防止大响应体502）  
    proxy_buffer_size 16k;  
    proxy_buffers 8 32k;  
    proxy_busy_buffers_size 64k;  
  }  
}  

# 在http上下文中添加全局优化  
http {  
  # 启用TCP_NODELAY（减少小包延迟）  
  tcp_nodelay on;  

  # 启用TCP_FASTOPEN（需Linux内核≥3.7）  
  tcp_fastopen on;  

  # 连接复用优化（适用于200M带宽场景）  
  keepalive_requests 1000;  
  keepalive_timeout 75s;  

  # 多核负载均衡（适用于112核服务器）  
  worker_processes auto;  
  worker_cpu_affinity auto;  

  # 大文件传输优化  
  client_max_body_size 500M;  # 允许上传大文件  
  client_body_buffer_size 128k;  
}  

# 修改注册表（需重启生效）  
# 增加TCP连接队列大小  
New-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" -Name "MaxFreeTcbs" -Value 20000 -PropertyType DWord -Force  
New-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" -Name "MaxHashTableSize" -Value 65536 -PropertyType DWord -Force  

# 优化TCP窗口大小  
New-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters" -Name "GlobalMaxTcpWindowSize" -Value 8192 -PropertyType DWord -Force  

# 禁用Nagle算法（减少小包延迟）  
New-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\<InterfaceGUID>" -Name "TcpAckFrequency" -Value 1 -PropertyType DWord -Force  
New-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\<InterfaceGUID>" -Name "TCPNoDelay" -Value 1 -PropertyType DWord -Force