Can I incrementally transfer all files in a disk while at the same time changing partition schemes and sizes?

Question

Currently I have an Ext4, 1TB hard drive in a Linux system where personal files are saved. The system files, including home folder, are in another (SSD) drive.

I want to format the SSD to install Windows, but then the Ext4 drive would at best be read-only (of course I am sorry for having chose Ext4 back then..)

Then I got the following idea, but I don't know how dangerous that may be:

1. Make sure to free a lot of space and leave the 1TB disk with at least 40% free space;
2. Use GParted to shrink the Ext4 partition;
3. Use GParted to create a NTFS partition occupying all free space;
4. Mount both partitions and move some folders from Ext4 to NTFS
5. Unmount both, srink Ext4 further, and expand NTFS to catch up with newly freed space;
6. Repeat steps 4 and 5 until every file has been transfered;
7. Delete (now empty) Ext4 partition;
8. Expand NTFS to occupy all available space.

Specifically, I'd like to know about risk of losing some files, or worse, losing all content from a partition or from the whole disk.

Besides that, I'd like to know how I could perform this operation in a safer way, if you think that is more recommended (I don't have spare disks around. I have a paid Dropbox Account, bit still I'd like to spare the weeks I would need to upload everything.

Answer 1

In theory, what you're suggesting should work, but I wouldn't want to try it on data I didn't have backed up. If you don't have the time/bandwidth to upload everything first, then the only real answer is to get another hard drive. They can be had for quite cheap - or could you borrow one from a friend? Also, I'd recommend a USB/eSata external HDD dock for these kinds of things. Much better than opening up your PC every time you want to swap a disk over.

Another thing to look at would be a backup service that sends you a hard drive to copy your data onto for the first run, instead of having to upload it. This could be cheaper than buying a drive and faster than uploading it all.

[Edited to add]In terms of the risk; I don't think I've ever lost data thanks to GParted, but I'd always make sure I've got a backup first just in case. In your own situation, it depends how irreplaceable those files are (family photos, PhD dissertation) do you want to risk even the smallest chance of losing them?