Strange behaviour on USB memory stick with Large files (5+ GB)

English Hardware
1

Hello

I have a strange situation. I have an 8GB USB 2.0 memory stick, I copy a 5.8 GB file to it, no problem at all, I check that the copy does finishes and that I can open the file.

I use lsof to see if any process has the file open to make sure the copy did finish. No file is listed so it’s suppose to be finished.

I ‘right click’ on it and select ‘safely remove’. Aaaand this is where things are a bit different.

KDE never tells me that the device was ‘removed’, it just shows a little ‘lock’ in the listing, but if I go to KinfoCenter to see the listed devices, it appears but on properties it says ‘not mounted’.

So I unplug the device. To check on it, I plug it on an XP pc, it lists the file but at 1.7 GB (more or less), so I ‘safely remove’ from it too and then I plug it back again to the Suse pc and no file is listed.

The USB device is formatted as NTSF.

Am I unplugging it when I don’t have to ? even if lsof doesn’t list any file using it or KInfoCenter lists the device as ‘not mounted’ ?

If I’m corrupting the device when I unplug it, then… how do I safely do it ?

I use OpenSuse 13.2 64b

Kernel 3.16.7-21-desktop.

2

Maybe you need to allow more time.

Writing to an NTFS file is slow.

Writing to a USB flash drive is slow.

You have combined two forms of slowness.

When I write on opensuse DVD installer iso to an 8G USB drive, it takes around 20 minutes for the copy to complete. And, after the copy shows as complete, it takes another 2-3 minutes before all of the buffers are written to the device.

In my case, I use “dd_rescue” to do the copying. At some stage it tells me that the estimated completion time is zero, and it looks as if it has finished. But the command does not exit until everything is on the device. Presumably it does a sync of some kind to ensure that.

Hmm, you could probably use dd_rescue for a file copy, too. You might need to install it first. It might give better diagnostics.

3

ok, I’ll try giving it a good amount of time after the copy is suppose toi be finished and also after selecting ‘safely remove’ before unplugging it

4

I have a cpu monitor widget on my desktop when it shows no activity I know that the commit and umount are complete.

Also used USB sticks can be very very slow to write because of the need to erase/recover data blocks. Flash memory has much different characteristics then magnetic

5

I do similar sometimes and it is sure to be that although kde tells you the copy is done, it is actually still writing.
The time it takes from when you start it to when kde tells you it’s copied, take that time and at least double it.

Also, even if you go to the safely remove option after you see the transfer complete notify, it’ll not eject the device until the copy is Actually complete, it will tell you eventually.
But as has been said it will take ages.
I’d assume about 1hr

6

I waited 30 minutes before selecting “safely remove” and it did remove the device immediately. I waited a few minutes and plugged again, file was there complete and readable. Safely remove and it happened immediately so I suppose the device is safe and can be mailed. Thank you!