I was an avid user of Linux for many years but switched to Windows. One thing that I have always missed is using rsync to make incremental snapshots for the purposes of backup. You use a command like this:
rsync -aP --link-dest=PATHTO/$PREVIOUSBACKUP $SOURCE $CURRENTBACKUP
and it will create a complete directory structure of the current state of the folder you are backing up, using hard links to reference the previous backup. Only new or changed files are actually written to disk; all the others are saved as hard links. This is just plain awesome, and none of the solutions I have found in Windows have been able to do this. (For reference, I've tried Windows File History, and paid money for commercial software including Crashplan and the otherwise brilliant Beyond Compare.)
Now that Microsoft have introduced WSL I have tried to do this in bash for Windows. It appears to have worked perfectly, but Windows is reporting the size on disk incorrectly, as shown here:
To explain, in one shapshot
snapshot-170831__07h08m48s I added a large video file, 1.40 GB, which took several seconds to copy. In the next shapshot,
snapshot-170831__07h09m09s the file took no time to copy, which suggests the hard link was created correctly and that no space has been taken up on my hard drive.
However all my Windows tools (Windows Explorer, Directory Opus, WinDirStat) report that the second snapshot folder is taking up 1.40 GB on disk.
The first question then is why is Windows incorrectly reporting the size on disk for these hard links?
But the more important question is should I be doing this: using Linux tools under Windows for my regular file backups. I've already seen on WSL that modifying files like .bashrc using Windows tools will make the file unreadable inside WSL. I wonder whether it is too risky to trust my backups to a tool like this, or whether I risk corrupting the file system and losing important files.