…or: Why I will not copy files using a GUI

This document was inspired by a thread on a mailing-list I have subscribed. The thread was about the speed of different file-systems (ext2, ext3, reiser, xft, …) One of the folks timed the speed using the KDE-Drag'n'Drop function.

So I took the time to time different methods of copying files. I also tried different 'locations' like a regular TTY or an xterm at different window-sizes.

I did not take different file-systems into account, since I do not think that speed is an important issue when choosing the FS. If I want a logging-FS for security reasons, I don't care for the speed-penalty I get for writing that log.

I used an old P3-600 for this test. Debian Woody is installed pretty much out-of-the-box. That means that there were not much optimizations like DMA for the disks or the like.

For the tests, I copied the contents of /dev/hda1 (my root-partition) to /dev/hdb1 I used the 'time'-command for timing. Read its manual-page for details

Here are some numbers for those interested

woody:~# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/hda1             3.9G  1.1G  2.6G  29% /
/dev/hdb1              19G  1.1G   16G   7% /mnt/hdb1
woody:~# uname -a
Linux woody 2.2.20-idepci #1 Sat Apr 20 12:45:19 EST 2002 i686 unknown
woody:~# find / | wc -l ; # Number of files
 144281

<table border="1" cellpadding="2" cellspacing="2" width="100%"> <tbody>   <tr>   <td valign="top">Command<br> </td> <td valign="top">Environment<br> </td> <td valign="top"><b>real<br> </b> </td>   <td valign="top">user<br>   </td> <td valign="top">sys<br> </td> </tr> <tr> <td valign="top">cp -ax / /mnt/hdb1/<br>   </td> <td valign="top">tty, 80x30<br>   (should not matter)<br> </td> <td valign="top"><b>15m21.664s<br> </b> </td> <td valign="top">0m15.380s<br>   </td> <td valign="top">5m6.830s<br>   </td> </tr> <tr> <td rowspan="3" colspan="1" valign="top">cp -axv / /mnt/hdb1/ <br> <br>   </td> <td valign="top">tty, 80x30 </td> <td valign="top"><b>22m8.563s<br>   </b> </td> <td valign="top">0m18.730s<br> </td>   <td valign="top">4m3.590s<br> </td> </tr> <tr>   <td valign="top">xterm, 142x53 </td> <td valign="top"><b>18m32.750s<br> </b> </td>   <td valign="top">0m30.840s<br> </td> <td valign="top">5m2.450s<br>   </td> </tr> <tr> <td valign="top">xterm, 80x30 </td>   <td valign="top"><b>17m27.710s<br> </b> </td> <td valign="top">0m30.790s<br>   </td> <td valign="top">5m5.190s<br> </td>   </tr> <tr> <td valign="top">Drag'n'Drop<br> </td> <td valign="top">KDE<br>   </td> <td valign="top"><b>23m28s<br>   </b>(Hand-timed,<br> +- 5 seconds) </td> <td rowspan="1" colspan="2" valign="top">not available</td> </tr> <tr>   <td valign="top">rm -rf /dev/hdb2/*<br>   </td> <td valign="top">tty, 80x30<br> (should not matter) </td> <td valign="top"><b>2m11.933s<br> </b> </td> <td valign="top">0m0.400s<br>   </td> <td valign="top">0m3.210s<br> </td> </tr> <tr> <td rowspan="3" colspan="1" valign="top">rm -rfv /dev/hdb2/* <br> <br> </td>   <td valign="top">tty, 80x30 </td> <td valign="top"><b>3m55.950s<br> </b> </td> <td valign="top">0m3.420s </td> <td valign="top">0m4.850s </td> </tr>   <tr> <td valign="top">xterm, 142x53 </td> <td valign="top"><b>2m20.204s<br> </b> </td> <td valign="top">0m3.040s<br> </td>   <td valign="top">0m4.720s<br>   </td> </tr> <tr> <td valign="top">xterm, 80x30 </td> <td valign="top"><b>2m20.208s<br> </b> </td>   <td valign="top">0m3.220s<br>   </td> <td valign="top">0m4.940s<br> </td> </tr> <tr> <td valign="top">Drag'n'Drop</td>   <td valign="top">gmc<br>   (konqueror did play tricks on me :-)<br> </td> <td valign="top"><b>3m40s<br> </b>(Hand-timed,<br> +- 5 seconds)</td>   <td valign="top"><br> </td>   <td valign="top"><br> </td> </tr>   </tbody> </table>

• File operations on commandline without the -v swich are fastest (by far!)
• When being verbose, an xterm can be faster that a TTY (I did not expect that. Probably depends on your graphic-adaptor)
• GUI is slowest. Not only by time.

It took me several attempts to hand-time the Drag'n'Drop.

1. The system crashed when accessing /dev/mem (This was never a problem on the commandline!)
2. When I came back from my coffee, I noticed that a dialogbox was waiting for my answer. This box appeared quite a while after starting the operation.
3. When I came back from my second coffee, I had missed the end of operation. While this is not really important in real life, it shows how inaccurate the 'remaining-time' display is.

I am not against GUIs. But if you need to copy a lot of files, take the keyboard. I usually try out the command with -v and when I see it works like I want it to, I hit <ctrl>+C and restart without -v. That way I can also spot error-messages, which is hard or impossible with verbose on.