What I've got:

  • The 40-pin 528 MB B+ Raspberry Pi
  • Five SATA hard disk drives

1) Is it best to use the four USB ports or find some kind of adapter for the 40-pin GPIO?

2) What do I need to make these five drives into a NAS with the Raspberry Pi?

  • 3
    GPIO won't be of much help, and you will get horrible speeds, but you should be able to set up a samba share and go from there - not sure about the raid5, but in any case let me repeat: the I/O performance will be horrible, especially if you want some sort of network connection as well – user2813274 Jun 22 '15 at 4:04
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    Yeah, after some research myself I found that the bottle neck in the Ethernet port can be somewhat helped but the io of the gpio and USB is terrible. My write speed would be under around 15 per second . I'm looking for an arm solution like the raspberry pi but built for multiple sata connections. – Joshua Robison Jun 22 '15 at 13:25
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    As an answer to this though , I found that the USB ports would be best and you can fix the speed of the Ethernet port easily. But I will find another hardware solution – Joshua Robison Jun 22 '15 at 13:27

I realize this is an old thread but it's still high on the Google ratings so an update. I've just built a NAS using a Raspberry Pi 4+ 4GB and four external 1-TB backup drives (Seagate Basic Portable STX1000400). The Pi's power over USB is insufficient to run four spindles, so it requires a powered USB hub, but this also has the advantage of spinning all four drives on USB 3.0 ports.

For setup I used RicMedia's excellent guide here: https://www.ricmedia.com/build-raspberry-pi3-raid-nas-server/. I then added WebMin for easier administration, and smartmontools (https://www.smartmontools.org/) to monitor the SMART status of each drive (note, watch the hardware compatibility on smartmontools, as not all USB drives play nice with smartctl over UAS).

The array won't break any speed records, but I have copied a single 1GB file to and from a Windows 10Pro PC over ethernet in about 9 seconds each way. When backing up a huge folder the backup went at about 1GB every 30 seconds. And if I ever want to expand, there's still another free USB3 port on the Pi, so another USB hub and set of drives should be hot-mountable (haven't tried this).

  • Thanks this was exactly what I was looking for on the subject. I'm thinking about a media NAS and wanted something like the Raspi4 to host it. – Michael McGarrah Jun 21 '20 at 19:49

1) The GPIO is useless for this purpose.

2) Your best shot is using 5 USB to SATA converters or one that provides 5 SATA ports on the same USB port. However, both of these solutions would be pretty slow, since the Raspberry PI's USB ports are all coming from a single USB port on the SoC. This means that you'll be limited by the 480Mbps of this single USB port. To make it worse, the Ethernet port is also actually coming from this single USB port, so, if you're downloading from the PI, in theory, you'll be sharing a bandwidth of 480-100=380Mbps over the 5 drives.

If all you want from a RAID setup is increased storage space and redundancy, go ahead. If speed is all you want, anything that doesn't already come wiht 5 SATA ports will be a bad idea in general for this setup.

  • It's a $35 NAS Controller, so you get what you pay for. But In principle it is functional and may be enough for low-bandwidth use. – crasic Dec 16 '17 at 5:50

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