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We will buy the BMPCC4k (This means 500GB/hour on a ssd), as we are a low/no-budget production, we can't have someone handling data.

I had the idea to use a rPI3+ to use for this. But I'm not sure if the rPI is able to handle this, he would be powered by a powerbank (20'000mAh).

When I insert the SSD, the hole SSD should be copied to a 4TB HDD.

So I have 4 questions:

  1. Can the rPI Power an external HDD (2.5" 4TB) + external SSD (Samsung T5 500GB) form the USB Power Source

  2. What's the average file transfer speed of the rPi from USB to USB?

  3. Is there a software which allready can do this (Preferable with a data validation)

  4. Which is the best OS to use for this? I'm only familiar with Raspbian, but can adapt.

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  • You won't be able to run the Pi and two drives from a powerbank. You might not even be able to run the Pi off it predictably. If you can, it will never last the seven hours Ghanima indicates it would take to transfer the data.
    – goldilocks ♦
    Jan 6, 2019 at 14:57
  • The idea might be feasible if you are not strictly limited to Raspberry. Not an answer because I never tried it and because it is not Raspberry, but there exist other brands of single board computers, inspired by the Raspberry success. See en.wikipedia.org/wiki/Comparison_of_single-board_computers and for example some ODROID models seem to support USB 3.0 and are currently available. No idea about the real world performance though.
    – szulat
    Jan 7, 2019 at 14:58
  • @szulat Ouh yeah. I was thinking about building a PCB myself to do it, but as it's quite critical that the data is safe, this isn't really an option for me. But I will take a look at the other SBCs :)
    – Timothy Lukas H.
    Jan 7, 2019 at 15:05

1 Answer 1

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The Raspberry Pi (all models) feature USB 2.0 ("Hi-Speed") only; which has a net data transfer of 40 MB/s at best (1); real life performance might even be less (2). Share that data rate between inbound (SSD) and outbound (HDD) traffic will yield 20 MB/s. So for 500 GB per hour that transfer is going to take about 25,000 seconds - which I believe are significantly more seconds than one hour has (about seven hours).

I doubt that this is a feasible approach if you intend to copy data during the production day. You'll need to look for faster systems that provide USB 3.x; preferable 3.1 or higher - dubbed "SuperSpeed +" - for a data rate in the GB/s range (Wikipedia#USB).

(1) USB 2.0 has a maximum signaling rate of 480 Mbit/s which is equivivalent to 60 MB/s ((Wikipedia#USB)). This results in a net data rate of 40 MB/s (de.Wikipedia#USB) due to protocol overhead and what-not.

(2) e.g. "SSD read test (reading 3.2GB) using a Pi3B came in at 35MB/s" (source)

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  • Thank you! It really seems this won't do it. It's 500GB/hour of footage. Not hpur of filming. But we'll probabbly film more than an hour/day :/
    – Timothy Lukas H.
    Jan 6, 2019 at 18:16

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