Question

我们有一个NetApp NAS文件管理器，它有时会出现故障，不确定这是否取决于网络问题，重负载或Filer本身;事情是，通常的System.IO.File.Copy(...)命令有时会意外地失败，而它在一分钟之前就会工作，并且在......文件管理器正在使用CIFS文件系统后一分钟再次工作。

在我的Log4Net日志文件中，我看到了异常：

System.IO.IOException：不再指定网络名称可用。在System.IO .__ Error.WinIOError（Int32 errorCode，String maybeFullPath）...

网络团队不确定会发生什么以及为什么，我现在正在考虑是否可以实现一个简单的尝试/重试系统来复制文件并在发生故障时重试副本，它可能是System.IO.File。复制不是为CIFS存储而设计的，而是针对普通的NTFS驱动器或稳定的网络存储。

是否有适合执行此操作的常见模式或.NET类复制并重试，还是应该使用类似以下伪代码的方法？

while(!copied && count <5)
{
  count++;

  try
  {
    //here copy the file
    ...

    //if no exception copy was ok
    copied = true;
  }
  catch
  {
    if(count >= 5)
    {
      // Log that retry limit has been reached...
    }
    else
    {
      // make thread to wait for some time,
      // waiting time can be in function of count or fixed...
    }
  }
}

Answer 1

对我而言相同。我有一段旧的NAS Server并不时Windows shows an error telling me that the drive is not accessible anymore 要管理file copy process，您可以使用CopyFileEx（来自Windows API），如下一个示例所示：

public class SecureFileCopy
{
    public static void CopyFile(FileInfo source, FileInfo destination, 
        CopyFileOptions options, CopyFileCallback callback, object state)
    {
        if (source == null) throw new ArgumentNullException("source");
        if (destination == null) 
            throw new ArgumentNullException("destination");
        if ((options & ~CopyFileOptions.All) != 0) 
            throw new ArgumentOutOfRangeException("options");

        new FileIOPermission(
            FileIOPermissionAccess.Read, source.FullName).Demand();
        new FileIOPermission(
            FileIOPermissionAccess.Write, destination.FullName).Demand();

        CopyProgressRoutine cpr = callback == null ? 
            null : new CopyProgressRoutine(new CopyProgressData(
                source, destination, callback, state).CallbackHandler);

        bool cancel = false;
        if (!CopyFileEx(source.FullName, destination.FullName, cpr, 
            IntPtr.Zero, ref cancel, (int)options))
        {
            throw new IOException(new Win32Exception().Message);
        }
    }

    private class CopyProgressData
    {
        private FileInfo _source = null;
        private FileInfo _destination = null;
        private CopyFileCallback _callback = null;
        private object _state = null;

        public CopyProgressData(FileInfo source, FileInfo destination, 
            CopyFileCallback callback, object state)
        {
            _source = source; 
            _destination = destination;
            _callback = callback;
            _state = state;
        }

        public int CallbackHandler(
            long totalFileSize, long totalBytesTransferred, 
            long streamSize, long streamBytesTransferred, 
            int streamNumber, int callbackReason,
            IntPtr sourceFile, IntPtr destinationFile, IntPtr data)
        {
            return (int)_callback(_source, _destination, _state, 
                totalFileSize, totalBytesTransferred);
        }
    }

    private delegate int CopyProgressRoutine(
        long totalFileSize, long TotalBytesTransferred, long streamSize, 
        long streamBytesTransferred, int streamNumber, int callbackReason,
        IntPtr sourceFile, IntPtr destinationFile, IntPtr data);

    [SuppressUnmanagedCodeSecurity]
    [DllImport("Kernel32.dll", CharSet=CharSet.Auto, SetLastError=true)]
    private static extern bool CopyFileEx(
        string lpExistingFileName, string lpNewFileName,
        CopyProgressRoutine lpProgressRoutine,
        IntPtr lpData, ref bool pbCancel, int dwCopyFlags);
}

public delegate CopyFileCallbackAction CopyFileCallback(
    FileInfo source, FileInfo destination, object state, 
    long totalFileSize, long totalBytesTransferred);

public enum CopyFileCallbackAction
{
    Continue = 0,
    Cancel = 1,
    Stop = 2,
    Quiet = 3
}

[Flags]
public enum CopyFileOptions
{
    None = 0x0,
    FailIfDestinationExists = 0x1,
    Restartable = 0x2,
    AllowDecryptedDestination = 0x8,
    All = FailIfDestinationExists | Restartable | AllowDecryptedDestination
}

有more extensive description in MSDN Magazine。

Answer 2

经过数周和数周的研究，测试和痛苦后，我终于找到了一个可行的解决方案，决定用Microsoft Robocopy command替换System.IO.File.Copy方法，该方法可以在Win Server 2008 R2和从第一次尝试起似乎运作良好。这让我很自在，我不是在重新发明轮子，而是使用完全符合我需求的经过测试的技术。无论如何，感谢大家的回答和评论。

安全地复制NAS Filer上的文件

2 个答案: