Copy corruption / Copy progress indicator fails

[Dr. Octagon]

Since LMDE 3 copying from an USB-HDD to an USB-Stick or vice versa has been characterized by the following facts:

The window, which shows the copying process with progress bar, closes BEFORE all data has been written to the other USB medium. With a 1 GB file the discrepancy between completion of copying and closing the window can amount to more than 5 minutes.
The progress bar runs very fast to the 75% mark at the beginning, then slowly approaches the 100% mark and then the window closes... The flashing of the destination USB medium tells you, however, that data is still being written. If you disconnect the USB medium immediately after the copy window was closed, nearly half of the data will not be available on the other media.

Maybe the indicator shows only the reading time of the root USB and not the follwing writing of the already cached amount of data to the destination USB.

I tested it several times with different USB media -> So this is definitely a bug.

Cu
Dr. Octagon

[Dr. Octagon]

I've retested and it also occurs in the following scenario:

When you save from USB to the computer hard drive everything runs as expected - the copy hint window closes when all data has been backed up to the hard drive.
If you now connect a new USB device and copy the data from the computer's hard disk to this device, the copy hint window is terminated too early again - I tested a 2 gigabyte file yesterday -> time delay after closing the window until the data is transferred to the USB device: 7 minutes.

Now I'm wondering: Am I the only one who is affected or has nobody noticed it yet, because there is always some time passing until you remove the USB device and it is therefore not noticed?

Cu
Dr. Octagon

[pioruns]

I did some tests trying to reproduce your experience. I tried to copy two 4GB files, one 2 or 4 GB file, smaller files, and other combinations.
USB-HDD -> USB-pen
USB-pen > USD-HDD
USD-HDD > desktop
desktop -> USD-HDD
desktop -> USD-pen
USD-pen > desktop

In each instance, everything was fine, and the copy progress window was waiting for a physical write to take place and it was synchronized with it. USD-HDD stopped blinking max. 5 seconds after window disappeared. So I could actually pull it out 5 sec after and it should be fine.
Only on one occasion, looks like Linux cached file into RAM, it kickstarted copy progress with 1GB already "copied". Then average speed shooted to the moon and started falling drastically with every second, to match real physical write speed to USB. At the end, it was synchronized again with the copy window progress, no problems.

Conclusion: cannot reproduce your problem. Using system from my signature, and 1TB Samsung USD drive (NTFS formatted), and two USB sticks, fast Sandisk 32GB USB 3.0 and slow generic 16GB USB 2.0.

Another observation: Looks like LMDE 3 uses some slow software driver for NTFS operations. Copying back and forth from USB-HDD and USB-pen formatted in NTFS, resulted with a saturation of some CPU cores and write speed was 40MB/s instead of 100MB/s my USB-HDD is capable off. Significant degradation in performance in NTFS. And high CPU usage during any operations on this filesystem.

[Dr. Octagon]

Thank you for your commitment.
Also tested again yesterday:
USB stick 2.0 plugged in... 1.1 GB file copied from desktop to stick. The copy indicator window shows me a write throughput of 64 MB/s constantly!? Impossible... and after a few seconds the window is gone. In the system control I can see: The process USB-Storage continues (with a constant change between "sleeps" and "not interruptible" status).
5 minutes later this process was marked in the system control as continuously "sleeps" and the stick stopped flashing (i.e. also "physically" no longer recognizing any writing process).

In summary, I can't confirm that anything has changed.

Cu
Dr. Octagon