Detect deleted files

[ghostryder333]

I'm only investing the effort to create an account here because I genuinely like the clean open source approach by the developer. However, I don't think Cobian will suit my use case with its current feature set.

I used to backup several Google Drive folders (completely mirrored to local directories) to two external HDDs with FreeFileSync in the past. I decided against Cobian back then because there was no git-like "Diff Tool" that listed all changes that would occur compared to the last full backup. However, I still managed to unknowingly delete files on my backup HDDs because FreeFileSync's integrated Diff View becomes pretty damn confusing once several hundred files change.

So, is there any way in Cobian Backup / Reflector to see exactly what files and folders will be removed at least? Generally, I would HIGHLY recommend a Diff View (or at least an integration for an external Diff Tool) as a future feature for Cobian Reflector. The way it is now I always have to use a Diff Tool such as Diffinity to compare the previous and the current full backup with each other to make sure I don't accidentally delete files in my backups. And obviously, this becomes extremely annoying if I have to do this each damn time.

I guess it shouldn't be that much of an effort to allow for the comparison of two files from the history pane within Cobian Reflector. It would just be another context menu entry that enables once two entries have been selected, and that (upon a click) passes down the paths to each backup directory to a parameterized command line call with configurable variables for the left and the right folder. For Diffinity a folder compare can be carried out on the commandline by just passing the paths + "-folderdiff" as arguments:

https://truehumandesign.se/diffinityDocumentation.php

It's just a matter of allowing the user to set custom parameters on the command line on some settings page in the preferences (like how Visual Studio supports external Diff Tools).

Obviously this is more tricky if you store the backups compressed, as uncompressing in advance takes time and storage. So you probably need to limit this behaviour to only uncompressed backups. Supporting compressed archives is likely more difficult and might require a custom implementation that's able to compare the compressed archive paths.

EDIT: Apparently Cobian Reflector isn't open source, which is a bit of a letdown. However, this still doesn't change the fact it's entirely free of any corporate clutter such as ads or enforced registrations.

[cobian]

I added the Mirror thing VERY reluctantly back in 2016 but with a big warning (from the help file):

"This question has been featured in the FAQ since forever, but people keep asking the same thing over and over again: "I want to make a backup of a directory. I delete some file on the original directory, but the program doesn't delete it from the destination".

Well, let me tell you: A BACKUP PROGRAM IS NOT A MIRRORING PROGRAM. And this is a very dangerous feature to add for a backup program. A backup is a ONE WAY copy. If you delete a file as a mistake or if a virus destroys your data, you will EXPECT to find your files in the destination. If you implement a mirror, you'll find NOTHING there!

Anyway, if you want to take the risk, you can make a mirror by checking the Mirror option in the advanced properties of the task."

But no, I will not work more on making easy to delete files where the function of a backup should only be to copy, not to delete.