Safe disk operations with C#

Question

I have a following question. Right now, we are writing out config files at shutdown. It happened that the user got a process kill during writing which resulted in corrupt configuration. Thus I have to make sure that the file on the disk is always correct, and no partially written files etc are there. Of course, I can implement some pattern using backup files myself (like write to backup, then replace the old file with the new one, some logic to detect and recover failed write.... ) but maybe there is a kind of a framework out there which handles this already?

you might have a look at the transactional file system that has been available since Vista. You'll need PInvoke to use it. An alternative is using a database instead of a file — Emond, Apr 04 '13 at 12:04

score 1 · Answer 1 · answered Apr 04 '13 at 12:08

Transactional NTFS, introduced with Windows Vista, allows to execute atomic operations on the file system (read, write, delete...).

Here's a managed wrapper you could use for .Net: http://archive.msdn.microsoft.com/txfmanaged

Do note that, sadly, Microsoft is considering deprecating this great feature of Windows. See http://msdn.microsoft.com/en-us/library/windows/desktop/hh802690(v=vs.85).aspx

score 0 · Accepted Answer · answered Apr 04 '13 at 12:23

You could write the configuration file to a temporary file and then replace the actual file with the temporary file by using the Sysyem.IO.File.Replace method:

string config = @"C:\my_config.xml";
string backup = @"C:\my_config.bak";
string temp = @"C:\temp_config.xml";

SaveConfigurationTo(temp);
File.Replace(temp, config, backup);

If you don't want to create a backup of the old configuration file, you can pass null as third argument.

See: File.Replace Method on MSDN.

Safe disk operations with C#

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