USB file copy hangs at 99%

Question

I am copying a file to a USB3.0 stick with an USB3.0 port using Ubuntu 16.04 with i3wm.

/dev/sdc1 * 8064 30277631 30269568 14.4G c W95 FAT32 (LBA)

To avoid problems related with the GUI I did the test using gcp

The copy of a 400MB file goes super fast until 99% (613.68 MB/s), then it hangs for like 30 seconds, and then it completes with an overall average of 10.22 MB/s (Time: 0:00:33)

Similar thing happens using nautilus or thunar. And seems to happen with any stick and any kind of file.

~~I expect the total transfer time to be way lower (e.g. 4 seconds)~~

Any ideas ?

You are right, write speed is declared 10MB/s so the total time makes sense. Still the "progress" seems broken though — stilllife, May 11 '16 at 11:31
Its the Cash beeing fast but running full: see the comment for this question:: http://askubuntu.com/questions/671239/file-transfer-is-freezing-while-copying/678892#678892
"Actually it was not freezing or hanging, it just filled up the cache (that is why it was faster at some point and suddenly looks like freezing.)

To make sure the copying running. You can do strace to see if system call I/O is running.

Open terminal, then ps -ef|grep <name_of_the_program> and then strace -p <prog_pid>.

answered Sep 29 '15 at 14:15

Muhammad Aizuddin" — Ken Mollerup, May 13 '16 at 12:48
Possible duplicate of USB pendrive : the copy takes about 3 minutes but the unmount takes a very long time : 10 to 12 minutes — PerlDuck, Aug 15 '18 at 12:30

score 0 · Answer 1 · answered May 11 '16 at 11:43

The realistic speeds of USB 3.0 hardly ever match the theoretical speeds and in some cases, the performance of USB 3.0 may fall below the performance of USB 2.0.

Since you have tried by both terminal and Nautilus, I feel there is some bug which is showing 613MB/s in both the cases. Nautilus messing up speeds, progress and expected time in some cases is known but I'm unaware of gcp's bugs.

Try testing your drive on another system and if you still get such results, please ask your manufacturer to replace the stick.

USB file copy hangs at 99%

1 Answers1