Why is it slower in Windows to extract rar files to USB/network storage?

25
2013-09
  • realdreams

    I noticed in Windows 7 extracting rar to local hard drive is always significantly faster than to network storage (CIFS) or USB 3.0, even when the external storage has better sequential write performance than the local hard drive

    I tested with winrar and 7zip and got similar results. Extracting to network storage (gigabit connection to FreeNAS CIFS) takes 3x longer, while cpu/memory/NIC usage are under 10%.

    Normally I can paste files into network storage for 50MB/s+ (limited by local hard drive), but extracting gets like 2MB/s.

    My guess is i/o latency really hurts performance in this type of application but I don't exactly know why. Does anyone have more insight into it? Thanks

    • Answers
  • Richard Powell

    Normally whenever you extract a big file, when it has finished extracting you can then see it copying to the location you have extracted to from a temporary location. I imagine this is the case too with network drives. It most likely extracts to a temporary location on your local hard disk first and then copies to the network drive.

  • Jason Bristol

    This is because you are transmitting over to a shared drive using windows SMB rather than using FTP (File Transfer Protocol) which is meant for transferring large files. The big drawback to using SMB is that it encrypts traffic on both ends, meaning since you are putting files onto a shared drive, your data is extracted, encrypted, transmitted, then decrypted, potentially scanned for viruses, and finally written onto the shared drive. This causes significant drops in speed. The recommendation is to use SMB for smaller files, larger files should be transferred using FTP. A good solution would be to extract to local, then transfer using FileZilla or similar software.


    • Related Question

    windows vista - Extracting a .zip file into Program Files (x86)
  • Evan

    I just got 64 bit Vista system after being on Windows XP. I'm trying to get all my useful programs up to date, and I've recently had a problem extracting files into the 32-bit program files directory (Program Files (x86)).

    I'm using 7zip to extract the eclipse-SDK-3.5-win32.zip directory into C:\Program Files (x86)

    Unfortunately, every time I've tried to do this, 7Zip reports

    can not open output file C:\Program Files (x86)\eclipse\...

    I've been able to extract it to C:\ and then move it, I'm assuming there's some protection on the Program Files directory that is causing some problems.

    Any suggestions?


    • Related Answers
  • Diago

    UAC protects the Program Files folders in both 32Bit and 64Bit. The only way around this is the method you've mentioned, or alternatively to disable UAC. The latter I do not suggest.

  • Peter Turner

    Do you need to have eclipse in your program files? If you put it in any other folder, (except c:\windows) UAC won't be an issue.

  • bk1e

    The access control list for C:\Program Files (x86) does not grant any write permissions to standard users. To see this for yourself, right-click on the folder in Explorer, select "Properties" from the context menu, and select the "Security" tab.

    Explorer in Windows Vista handles permission failures by attempting to elevate to Administrator privileges, hence the UAC prompt when you drag a folder into C:\Program Files (x86).

    7-Zip does not handle permission failures by attempting to elevate to Administrator privileges. If you want to run 7-Zip as an Administrator account in order to install software into the Program Files directories, find the icon for "7-Zip File Manager" in the Start Menu, right-click on it, and select "Run as administrator". Now you can pick up anything.

    What you're already doing is also perfectly reasonable: extract archives as a standard user and move the extracted files into Program Files, taking advantage of Explorer's UAC prompts.

  • Peter Turner

    Another answer would be to run 7-Zip without themes enabled (ala win2k). If you do that, then you might just wind up with Eclipse in your own user folder even though you think you're putting it in the program files folder.

  • svandragt

    I have the same problem with WinRar. However when dragging the files into an Explorer window from the main WinRar window a prompt appears that you canauthorize this action to have the files extracted in that location.

  • Canadian Luke

    Go to the folder where you installed 7Zip or WinRAR (for WinRAR: C:\Program Files\WinRAR or C:\Program Files (x86)\WinRAR), right click WinRAR.exe or 7zip.exe -> Properties -> click the Compatibility tab and check the "Run this program as an administrator" option