Microsoft Windows has supported a feature called Shadow Copy since Windows Server 2003, using Windows 2000 or newer as the client.
Shadow copies, better known as “Previous versions”, by many users are kind of snapshots of a filesystem (“drive”, for Windows users) taken every so often. It is not a replacement for backups or RAID, just a convenient method to access old versions of your files. Thin of it as a revision control system for any file, save for “revisions” are taken at time intervals instead of evey time there are changes, which means not all the changesets are “captured”.
Samba implements the server part of shadow copy since version 3.0.3, released in April 2004, and makes them available to Windows clients.
On the Unix world, you can get more or less the same features, albeit only locally (not for NFS or Samba shared folders), by using filesystems such as ZFS, HAMMER (apparently, only available on DragonFly BSD), Btrfs, Zumastor and many others. The main problem being adoption of those solutions is marginal, and not available through the network (“shared folders”).
Sun (now Oracle) implemented a “Previous versions”-like feature for ZFS snapshots in Nautilus in October 2008:
KDE once had something like that but for the ext3cow file system. It was an application called Time Traveler File Manager (user manual, interface design and details) by Sandeep Ranade. Website is down and ext3cow is effectively dead now.
By this time you probably have guessed my wish for today: implement “Previous versions” support for Samba, ZFS, etc in Dolphin, the KDE file manager, or even better: in KIO, so that it is available to all KDE applications.
There’s something like that in the working for Fedora / Gnome:
https://fedorahosted.org/snap/
Would be even cooler if that was integrated with a REAL backup solution and not only snapshots/shadow copies. I tried something like that once but my programming skills were too limited 😉
If implemented in KIO, it would be fun to see how you’d solve the “save” function. update the last modified times and data in the snapshot and try to patch one step at a time all the way up to today? =)
… I would like to see a nice collection of the hourly-daily-weekly-monthly folders from rsnapshot. As rsnapshot does not change the data structure creating such a collection should be an easy task. During kde3-times it was easy to extend the file property dialog with own tabs, but I do not know how this works now in kde4.
I’m thinking about ZFS/Dolphin integration, I know too little to say that I’m going to implement it, but who knows?
@Jonas
Snapshots are taken automatically, you do not have a “take snapshot” button (at least it was like that last time I tried on Windows Server)
Any news? I would love to see that ability in Dolphin file manager!
Is possible to use any archiver tool (like zip or tar) for backup folder every time when it changed. Hardest thing – write a sexy and convenient plugin for Dolphin.
Done! 🙂
http://kde-apps.org/content/show.php/Autoversion?content=144977