Optimizing disk writes

If your site creates many new files on disk, such as files uploaded by visitors, consider these performance improvements:

• Avoid head seeks

• Use FileStream.SetLength to avoid fragmentation

• Use 64 K buffers

• Disable 8.3 filenames

Avoiding head seeks

Writing bytes sequentially without moving the read/write head happens much faster than random access. If you are only writing the files and not reading them, try writing them on a dedicated disk drive using a single dedicated thread. That way, other processes won't move the read/write head on the drive.

Using FileStream.SetLength to avoid fragmentation

If multiple threads write files at the same time, space used for those files will become interleaved, leading to instant fragmentation.

To prevent this, use the FileStream.SetLength method to reserve enough space for the file before you start writing.

If you use the ASP.NET FileUpload control to receive files from a visitor, it can give get the length of a file as shown:

int bufferLength...