File transfer: speed and time issues comparing to Windows

doomguy84 · 2019-01-30 14:28:39

Hello!
I used many distros with different DE, now I'm on archlinux+gnome and archlinux+lxde but the issue still remain.
When I just copy a file from the pc to usb flashdrive, the transfer starts with "incredible" speed (maybe 4x speed of usb capable) and obviously some time after the speed decrease to 0, then I have to wait and the "regular" speed start.

I also try with command line using "pv", but no changes.

Why?
Someone else got this?
How can I resolve?

I don't think it is an hardware problem because on the same pc with the same usb flashdrive if I copy/transfer a file using Windows 10 the speed (and the graphs) is regular from start to end, and AT THE END I know I can unplug the usb drive, but no with Linux, because sometimes it says the transfer is 100% within seconds but I have to wait until the "real" transfer is completed.

I hope I explained right the problem.

seth · 2019-01-30 15:46:51

The file is read into the cache w/ ludicrous speed™ and then written onto the USB.
This is normal, the only proper measuring would be to poll the destination size (which afaik no tool does and what would slow down the process)

You can limit the file cache, but that's not advisable.
https://superuser.com/questions/1110655 … g-in-linux

fromagegb · 2019-01-30 19:15:39

I had similar problem creating an iso "live" usb, and found I had to run "sync" on the command line - when the cache has copied to usb it tells you, I can't recall how, probably by getting the prompt back. That solved my problem.

seth · 2019-01-30 19:42:08

Running sync will flush the file cache and perform any pending disk writes - he's rather concerned w/ a linear progress display.
Also an explicit "sync" should not be required when using dd (and in doubt it has an oflag for that)

doomguy84 · 2019-01-31 08:28:38

ok, thanks, but...
why Windows show the effective and real speed/time like this and linux don't ?
https://filestore.community.support.mic … 334f98b692

you (seth) said "The file is read into the cache w/ ludicrous speed™ and then written onto the USB"
Windows does not do that?
is there a way to just copy a file from A to B without use cache?
should I use sync or terminal commands everytime I want to copy a file??

I suppose that copy&paste a file is a very simple operation

Last edited by doomguy84 (2019-01-31 08:53:12)

seth · 2019-01-31 08:42:16

Avoiding the cache or enforcing sync operations is possible but stupid (between slowing down stuff to harming the NAND memory)
I've no idea whether windows does that or just estimates the time (from file size and device speed) or polls the destination.

No you do not have to use the terminal for copying, what you *HAVE* to do (on windows and linux) is to unmount the device (at which point it will be synced) - windows calls that "safe remove" or so.
formagegb's comment revolves around a case where the device is accessed directly (w/o a filesystem) and (probably) a bug that existed in a tool ("dd") severaly years ago.

"Copy & Paste" has *nothing* to do w/ file transfer (that actually works entirely on a cache and will usually just be the URI)

Please remove the image (replace it w/ a link) - the accepted board limit is 200x200px.

doomguy84 · 2019-01-31 08:53:59

ok, thanks
sorry, I edited post removing img

Arch Linux

#1 2019-01-30 14:28:39

File transfer: speed and time issues comparing to Windows

#2 2019-01-30 15:46:51

Re: File transfer: speed and time issues comparing to Windows

#3 2019-01-30 19:15:39

Re: File transfer: speed and time issues comparing to Windows

#4 2019-01-30 19:42:08

Re: File transfer: speed and time issues comparing to Windows

#5 2019-01-31 08:28:38

Re: File transfer: speed and time issues comparing to Windows

#6 2019-01-31 08:42:16

Re: File transfer: speed and time issues comparing to Windows

#7 2019-01-31 08:53:59

Re: File transfer: speed and time issues comparing to Windows

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