4gb drive occupation difference, with identical files on both drives

[Istria]

Hello people,

I have 2 external HDDs.
1x Seagate Backup Plus Slim 2TB (bought in 2014)
1x Toshiba Canvio Basics 2TB (bought last week)
Both are NTFS.

What I did was copy the entire contents of the older drive to the new one. Simply CTRL-A, CTRL-C, CTRL-V.

After finished, I noticed a 4GB difference in occupied space in Windows Explorer (right click, properties). The new drive has 4gb more on it than the older one.
I've ran FreeFileSync (both ways), it found no differences. Also File Tree gives identical folder sizes, down to the last byte.

Anyone an idea what the cause of this 4gb difference is?

What I want to do next, is format the old drive to EXT4 or maybe ZFS, and copy all the files back to it from the new drive. But this is basically my whole life. All family/childhood pictures, videos, documents, etc. Because of the size difference, I'm afraid something might have gone wrong and I'll find out I lost a lot after formatting the original drive.

Any suggestions on how to verify the data is intact on the new drive?

 

[ccssid]

Exact files (Copied) have a different size on disk on the same drive?

Recently I've run across something odd. An exact copy of a folder full of files has a different Size on Disk than the original. I could understand how this could happen between drives with different

superuser.com

 

[Istria]

Thanks. At first I thought that was it, although it didn't make complete sense it was a 4GB difference. If its all <1kB files, there should be 4.000.000 files. And there are only 250.000 files in total on the drive. Assuming the file count does not suffer the same problem.

What I did next was a "file content comparison" in FreeFileSync instead of only comparing file size and last modified time. This compares every file to the bit level if I understand is correctly. It took 24h, but after that, there still were no differences found. So I felt comfortable enough to proceed:

Formatted the old Seagate drive to EXT4. Copied back all the files from the Toshiba. Now I would expect to find an identical file size, but I still don't. See attachment.

Could it have something to do with PMR vs SMR drives? The Toshiba turned out to be SMR. My old Seagate is not. Not sure if CMR, PMR or something else.

 

[ccssid]

One thing that i do when "copying" a bunch of large files from one drive to another....Not use ctrl-c, crtl-v, but use a file syncing program. Which you did after the fact. I have been using Allway sync for the past several years and have been very happy with it. I sometimes use Allway sync to back up my server as well as rsync.

In the past, when i did use crtl-c, crtl-v, there were always some files that plain and simple did not copy and paste.

 

[Istria]

After formatting the Seagate to EXT4, I copied all the files back using FreeFileSync instead of copy/paste. The picture above is the result of that.

The size difference has gone down from 4gb to 200MB. But as I understand it, it should not be the resident files the way I did it.

 

[ccssid]

Glad it worked out

 

[Istria]

Well, it worked out in the sense I just took a deep breath and went for it. But I still don't understand the 200MB size difference. The NTFS (BACKUPDRIVE) is 200MB larger than the EXT4 drive. If the NTFS drive has 'hidden' resident files, it should show less used space instead of more, correct?

 

[ccssid]

in a sense, I am not the most technical guy. I am just able to get things to work for my purposes. I notch this one up as sh&t happens.

 

[Istria]

To be honest I also don't care that much about the exact technical explanation. But I'd just like to be 100% sure all my pictures are still there and not corrupt. And apart from opening every single picture and watching every single video from start to end, the best next thing I could think of was the "file contents" comparison from FreeFileSync. But that is where I "took a big breath and jumped" and reformatted the thrusty old Seagate to EXT4, because I wasn't sure it was a good enough check.