Atomic file copy under .NET

Question

I am building a server app that copies files using System.IO.File.Copy(...) function. My files can be rather large, therefore, it has a fair chance that if the machine crashes, it happens during copying.

After restarting the service, I should be able to pick up the copy tasks and continue. How can I detect if a copy has been successfully completed or interrupted by server crash?

My current plan is to copy the files to a temporary name and once copying completed rename it to the final name. This way the file naming is able to carry the state information over the crash.

Do you have any good/better suggestions?

EDIT: Target OS is Win2003, therefore transactional NTFS is not available

Answer 1

Transactional file system.

Answer 2

Newer versions of Windows allow you to use transactions .

Answer 3

Other have suggested transactional NTFS which is fine if you're deploying on Vista or later. If you need to support XP (or earlier) then temporary file followed by a move (rename) is the best solution.

The answer to this similar question provides more info: http://stackoverflow.com/questions/774098/atomicity-of-file-move

Answer 4

Check out Background Intelligent Transfer Service in Windows Server 2003. It provides the mechanism of jobs, which can be paused and resumed even after restart.

Here are a few samples how to use it with .NET:

Write Auto-Updating Apps with .NET and the Background Intelligent Transfer Service API

SharpBITS.NET - wrapper for BITS API