I am using a Raspberry PI as a NAS (raspbian). Everything works quite fine, however Samba is giving me a bit of trouble. Basically what happens is, that on large file readings it kind of "hangs" after copying a few hundred MB making the disk unaccessible (even by other means), forcing me to reboot the entire system. Writing and browsing seems to work flawlessly. The same happens with SFTP after a longer while. When transferring, the CPU load on the RasPi goes to 100%, so could this problem be caused by the weak CPU? I overclocked it to 950 MHz but to no avail. The logs also don't reveal anything.

Another Idea I have is the USB port. The raspberry offers only a very little amount of voltage. The HDD I use is self-powered but maybe there is a problem with the USB port.

  • 1
    Welcome to StackExchange! I've stopped short of down-voting as it's actually a decent question, but ServerFault is for professional systems administration questions - your question may be better placed on SuperUser, so I've flagged it to be moved there :)
    – Craig Watson
    Commented Jan 19, 2014 at 15:25

2 Answers 2


As the Pi can supply limited current (depends on what other peripherals you have connected) it is not a good idea to use an external HD without a powered hub. Many HD require up to 500mA - which is definitely not possible.

You may have other problems, but you should eliminate this first.

  • Keep in mind that the HDD has it's own power supply, so the USB port on the RasPi is used only for file transfer, so could this be the problem anyway?
    – Martin
    Commented Jan 20, 2014 at 11:01

It's a known issue with the Raspberry Pi. The Ethernet chip and the USB ports reside on the same USB bus. Driving both hard simultaneously (by copying large files to/from the USB drive over a network connection) can cause the USB subsystem to fail, requiring a reboot.

You can read more about the Raspberry Pi's USB issues over here.

Bottom line: the Raspberry Pi's USB subsystem was made for low speed peripherals like keyboards and mice. It was not meant for high-speed transfers.

There was some talk that this was a driver issue and could be fixed using a software update, but I have not kept track of it.

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