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When used first time, write to USB gave only 200Kb/sec speed o.O Like 3 hours for 300MB copy.

I formatted the USB as EXT4, and tried again, the speed went up to 1.6MB/sec, but then quickly fell down to 400KB. Sure, it's wayyyy better but still cannot believe this is the way to make large copies of several GBs. Am I missing something? I mean, if I need a backup for my Home, it would take me whole night.

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  • What kind of USB device is it, a hard drive? flash drive? A spinning drive can be quite slow. – djsmiley2kStaysInside Mar 9 '17 at 19:14
  • Can you invoke lsusb -t? On my Kubuntu it displays e.g. Driver = ehci-pci/2p. The OHCI/UHCI are the two industry standard USB 1.1 interfaces whereas EHCI is for USB 2.0 and xHCI is compatible with all of the previously mentioned interfaces including USB 3.0 (source). Confirm the bus you use is seen as EHCI. – Kamil Maciorowski Mar 9 '17 at 19:29
  • It's a flash drive. The lsusb -t tells me it's xHCI driver, 2 of them actually, one 8p 5000M (dont know what is that) and another one 16p 480M – dgan Mar 9 '17 at 21:06
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Before digging into your software, you need to benchmark your pen drive. Go get access to a Windows computer, and run a benchmark like this ATTO bench, you might be surprised finding actual speed of your write operations on a low-end pen drive.

If you see write speeds on large data blocks in 2-3MBps range, throw it away and get one of USB 3.0 dual or quad-channel pen drives, they will perform up to full theoretical USB 2.0 speed (~35 MBps) on USB 2.0 controller.

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  • oh. Well after test ( dd if=blabla of=blabla), it turns out I have 15 MB/s read, and 3.1 MB/s write. But still, it would be great to achieve them IRL, not only during test – dgan Mar 10 '17 at 19:13

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