writing data to disk message... when safely remove USB drive

[Amichai Rotman]

That's the way Linux saves data to disk. When you transfer a large file to
an external device (not part of the local file system), it keeps the data
in a memory cache. The kernel finds the best time to periodically flush
that cache to disk.

You have two options to run after the progress bar disappears:

1. Click Safely Remove and wait until you get the "It is now safe to remove
the..."
2. Drop to a Terminal window and run 'sudo sync' - and wait until the
prompt comes back (that is what I do when I transfer large sized files).
3. Unplug the USB device (be it a USB stick or external hard drive.

Your files are actually written to the external drive at that point. if you
skip that stage (2), the copy operation is cancelled.

Amichai.



On Sun, May 5, 2013 at 3:17 PM, Basil Chupin <blchupin at iinet.net.au> wrote:

> On 05/05/13 20:10, Jkhatri wrote:
>
>> On Sunday 05 May 2013 03:31 PM, Colin Law wrote:
>>
>>> On 5 May 2013 10:54, Jkhatri<khatri.jatin at gmail.com**>  wrote:
>>>
>>>> Dear ALL
>>>>
>>>> I'm facing one strange issue, whenever I copy some data to USB thumb
>>>> drive (
>>>> some big files, say 2GB .avi or something) its displays progress bar on
>>>> screen that data is being copied to disk and finally it finished but
>>>> strange
>>>>
>>>>
>>>> why like that ???
>>>>
>>>> several minutes after the copy before attempting to eject you should
>>>> find it then ejects immediately (as the write is complete).  If it
>>>> becomes very slow on a particular stick that probably means that it is
>>>> failing as it takes longer to write as the flash wears out.
>>>>
>>>> Colin
>>>>
>>>>  Thanks for your quick reply, colin
>>
>> but same drive works fine with M$ windows, on same PC ( dual boot ). it
>> copies same file quickly, and I'm able to eject it as soon as copy process
>> completed. But it takes long time in Ubuntu it takes dual time, like  copy
>> time + safely remove message progress bar time
>>
>> both windows and Ubuntu are 64bit version and installed on same laptop (
>> dual boot )
>>
>> Thanks
>>
>
> You get fast copying in M$ because the stick is formatted in msdos.
>
> Writing from Linux to a msdos formatted drive, such as your USB stick,
> takes "for ever". There is a very complicated explanation for this but
> believe me it is true (something to do with the kernel).
>
> Format the USB stick in a linux format, say ext4, and you will find that
> the copying will be fast (and even faster if the USB is usb3 and connected
> to your usb3 port on your computer; usb2 you will get around 28MB/s but
> with usb3 you should get around 110MB/s [but depending on the brand of
> stick you have]).
>
> BC
>
> --
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> AMD FX 8-core 3.6/4.2GHz processor
> 16GB PC14900/1866MHz Quad Channel Corsair "Vengeance" RAM
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>
>
>
>
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