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I have an QNAP TS-210 NAS and it seems, that there's a Debian Linux on board. I've installed Midnight Commander there and have been using it successfully for years. Today I spotted something weird.

I have to move a large collection of movies (around 130 GB) from one folder to anther. Movies are split into many subfolders. Whenever I enter any particular folder, select all files in MC and press F6 to move them to destination, everything is fine. But, when I attempt to move entire subfolder (destination has it as well, but files inside are different, so there is not overwrite in any case), process takes very, very long. It actually looks like my NAS would be doing a copy, instead of move of this file.

Is this normal condition? When I'm doing the same operation on Windows, move process always is very, very fast, no matter, if I'm moving entire folder or only its contents.

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mv works in two ways. mc moves behave the same way.

  • If the files are on the same logical device (partition or disk), only the directory entries are moved. This can be extremely fast.
  • If the files are on different logical devices, the files are copied and the old file deleted after the copy is done. This is relatively slow as the file must be read, and then written.

If your NAS has multiple disks, then moves may result in data moving between devices. You can check which directories are mounted (and their space utilization) with the df command.

  • Thanks (+1). But, what you're saying, is -- of course -- obvious to me. But, I'm not sure, if we're talking about the same. No matter, whether I'm moving contents of a subfolder (share/Download/Subfolder/*.*) or just the entire subfolder (share/Download/Subfolder), I'm moving files, that are stored in the very same physical location. So -- in my opinion -- move process should have the same speed in both scenarios. It hasn't. So, either I'm missing something obvious about how mv works or something obvious from your answers. – trejder Nov 17 '14 at 7:38
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I have nothing to support my statement other then empirical knowledge but I think mc doesn't completely behave the same as mv. I just stumbled upon this question as I was experiencing slow movement of files by mc whereas mv was instant. The problem seemed to be ownership of files. When I move files in mc, ownership is changed to the current user running mc and it takes forever. When I move by mv command, the move is instant and ownership is kept original.

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