I wish to build myself a NAS and I figured that a 32GB SDHC (on which the Arch Linux ARM is installed) won't quite cut it. I would very much want to connect my 2TB Seagate Expansion Drive but how safe would it be to keep it connected like all the time?

My concerns usually deal with

  • The likeliness of any corruption of data that may occur due to the waves transmitted as the hard drive is magnetic in nature and kept in the close vicinity of the Pi 4.
  • The likeliness of data loss due to power outage as such an event would take place abruptly and there would be no time for measures like unmounting and all to have taken place.
  • Is the Pi 4's USB3.0 port capable of providing sufficient power to the external magnetic hard drive? It might require more power than solid state drives due to moving parts. :P

I would be thankful to have answers of these questions.

Sincere apologies for my bad English.

  • What "waves", and what transmits them?
    – Andreas
    Nov 17 '20 at 14:36
  • 1
    This is probably safe as long as whatever is powering the Pi can supply enough wattage. I have a CanaKit Pi 4 kit with a USB C adapter that causes intermittent undervoltage on my connected WD Elements drive (which is bad). If you ever see a message appear that the drive was unplugged, and you didn't actually do anything, take it down immediately. Otherwise, that will cause data corruption. You need both a very good power supply AND a very good quality cable, but there's no reason this should be impossible. If you have the funds to purchase a USB SSD, that will also work much better. Nov 17 '20 at 18:51
  • @Andreas By waves, I mean the WiFi signals with which the Pi is connected to the router of the home network. I am inexperienced with the wave theory so I do not quite know if it is supposed to cause harm. Nov 21 '20 at 4:14
  • A good power supply and a good cable. Thanks @RDragonrydr, I will certainly keep that in mind. Also, I do have the same hard drive as you do, apart from the Seagate one so I think I would try that too. Nov 21 '20 at 4:15
  • @AkashdeepDhar I thought so. Not even a strong magnet will damage your drive, so I would not worry about faint EM radiation. I have my Pi permanently resting on top of my WD enclosure.
    – Andreas
    Nov 21 '20 at 11:33

To add to Shivang's answer:

  • I've used a "spinning disk" USB drive powered from one of the USB3 ports on my RPi 4B for over a year now, and on a 3B for years before that. It runs 24x7, and I've not had any power-related issues.

  • The USB ports with the "blue tongue" are USB3, and you will get a little better data throughput on those.

  • Wrt data corruption: Format the drive for ext4 file system. ext4 is a robust file system that is resistant (not immune) to data corruption.


To answer your questions sequentially:

  • If you are using a portable external hard drive from a reputed manufacturer, the enclosure should have vibration pads inside to protect the drive from shocks and vibrations it would incur from regular usage. The Pi board itself doesn't generate any vibrations and a fan attached to it wouldn't be able to generate enough tremors to affect your HDD in any significant way.
  • If your residence is prone to power outages, it is recommended to use an external power source such as an UPS with your computing devices. They provide enough time for you to power down the systems safely and newer models even send a power down signal for you. The same advice is also applicable to the Pi and its connected peripherals. You will risk data loss if your Pi and the connected HDD lose power abruptly.
  • The Pi 4's USB 3.0 ports are perfectly capable of powering external HDDs which generally require up to 500mA and rarely anymore. For reference, the Pi 2 and up can deliver up to 1.2A via their USB ports. (Source)

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