NTFS Find and NTFS Backup

When using a Windows system with Interix or as NFS server, it can be difficult to backup all the files on a NTFS volume. This is because NTFS has many features not widely known in the Windows community and with little to no support in the Windows GUI. These features are used, however, e.g. by the Interix subsystem or the NFS server. In particular the interesting NTFS features are:

Unicode filenames with chars not convertable to ANSI
NTFS hardlinks
case sensitive filenames
reparse points
symbolic links
alternate data streams
pathes longer than 260 characters
ACLs
compressed files
sparse files
and possibly others

Most backup programs unfortunately can't handle several of these NTFS features, so I decided to start my own copy program written in Perl, which is meant to be used as a backup solution for NTFS volumes. The idea is to simply copy all files to another NTFS volume (e.g. external HDD drive) while preserving all of the NTFS features. To save space, it should be possible to clone an existing backup on the external HDD by creating hard links for each unchanged file to the existing backup. Several backups can be stored in a space efficient manner, and restoring doesn't require a special software.

The backup program comes as a Perl module called Win32::NtfsBackup. As a side effect I wrote a Perl module called Win32::Find to traverse a NTFS directory tree, similar to Perl's File::Find, but with support for NTFS features.

A similar idea for backing up files has been followed by this rsync approach, but unfortunately rsync on Cygwin can't handle case sensitive files, alternate data streams and ACLs. There is also Robocoy but that unfortunately can't handle hard links. Also it can't be case sensitive.

Current status

My NTFS backup script is written in Perl. You need ActivePerl and the Win32::API package to use it. As Win32::API is not yet available for ActivePerl 5.10, you should use ActivePerl 5.8 for now.

Download current version

History

2008-06-21: alpha release 0.02, support for copying hardlinks
2008-06-09: initial pre-alpha release 0.01, which supports Unicode long file names, case sensitive file names and streams.

TODO

Think about API to get it more general purpose useable
Implement other NTFS features

technical solved problems

Pathes longer than 260 characters: use \\?\ prefix and Unicode filenames.
Case sensitive file listings: use FindFirstFileEx() with the FIND_FIRST_EX_CASE_SENSITIVE flag.
Case sensitive file creation or opening or deletion: use CreateFile() with the FILE_FLAG_POSIX_SEMANTICS flag.
Creating hard links case sensitive. CreateHardLink() has no flags for this and cannot be used. But opening the existing file in case sensitive mode and then BackupWrite() with a BACKUP_LINK structure works. This was the only official way on NT4 to create hardlinks.

technical open problems

Creating new directories case sensitive. CreateDirectory() has no flags to switch.