I'm planning to use my Raspberry Pi as a download box. I'm going to store the files on a network location, mounted in /mnt/, and use the Raspberry only to run the client.

Theoretically, the files should just be passed on to the network storage. But will it in practice mean that things are written to the SD card (albeit temporarily?).

I want to avoid wear on the SD card, so if files aren't only passed on I should perhaps make use of a USB stick instead of the SD card.

  • 1
    A USB stick will have similar wear "problems" as a SD card, both are based on NAND. The same would apply for a USB SSD. However with a USB stick or SSD (and perhaps some recent SD card as well), the firmware might do a good job as spreading the wear level. So with recently manufactured cards/sticks this might be less of a problem.
    – Huygens
    Dec 1, 2015 at 19:55

2 Answers 2


The only scenario I can think of is if RAM buffers fill up during the copy. That might trigger the system to move a program or data to swap space (on the SD card).

I do not think that likely, even if it is possible. I suppose you could discount that possibilty completely by disabling swap space.

sudo update-rc.d dphys-swapfile remove

should remove swap on a Pi.

  • Take care that the application could still write some data in /tmp or /var/cache or /var/tmp (or anywhere under /var). And also generate logs under /var/log. You can check if an application has opened file using the lsof command: lsof -i <pid> and replace <pid> with the PID of the process you want to check.
    – Huygens
    Dec 1, 2015 at 19:53

If you write to a mounted network drive there is no reason why the Pi would write to the SD card. Unless your download application uses the SD card for temporary storage until the file has been downloaded. This would be easily fixed in the application's config file.

Lately this forum is flooded with people scared about worn out SD cards. While it is theoretically possible, IMHO chances are low it's going to happen.

So again, people, unless you're moving tens of Gigs every day like there is no tomorrow, please stop being scared about flattening out your SD.

  • Depending on the size of the SD cards wear can be more noticeable. On a 4GB card, you probably will more quickly reuse the same cells for writing than on a 32GB one, for the same work load. I've experienced it on a $GB card, it is still usable, but I had to reinstall Linux because the FS was damaged.
    – Huygens
    Dec 1, 2015 at 19:50

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