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FYI, RPi 2 runs nicely from USB hard drive

Posted: Sat Feb 28, 2015 9:15 pm
by mikronauts
The Raspberry Pi 2 is quite capable of being used as a development system, so I’ve decided to make a dedicated RPi2 development box I can ssh and rdp into from anywhere in my network.

Take a Raspberry Pi 2, a 3TB Toshiba 7200rpm drive, a USB3.0 hard drive enclosure (shaken, not stirred) and a bit of configuration, and now I have a nice little Pi development box.

It feels noticeably snappier for desktop use than running of an SD card, best guess is that the faster disk reads outweigh the slower seeks when loading large apps.

http://www.mikronauts.com/2015/02/28/ra ... enclosure/

Re: FYI, RPi 2 runs nicely from USB hard drive

Posted: Sat Feb 28, 2015 9:32 pm
by Jim Manley
mikronauts wrote:It feels noticeably snappier for desktop use than running of an SD card, best guess is that the faster disk reads outweigh the slower seeks when loading large apps.
Pretty much any hard drive is going to be upwards of 50 ~ 100% faster than any SD card because the USB bus is capable of higher throughput than that of the SD card port due to limitation of the SD card port to only operating at 3.3 volts, not the 1.8 volts that highest-speed SD cards need to operate at their maximum transfer rate.

I assume you know that a USB 3.x interface/device is going to be wasted on the Pi because the USB bus on the Pi is limited to USB 2.0 speeds. If 3.x is all you have on a latest-technology device, it will operate at the slower rate, but a bunch of dollars will be circling the drain.

Re: FYI, RPi 2 runs nicely from USB hard drive

Posted: Sat Feb 28, 2015 9:43 pm
by mikronauts
Totally agreed, and it matches my test result from http://www.mikronauts.com/raspberry-pi/ ... ter-tests/.

USB 3.0 is wasted when using hard drives - but I found that I get significantly better network throughput using a gigabit USB 3.0 adapter (176Mbps) with a Pi 2 than using the 10/100 Ethernet (94Mbps) on the Pi 2 (see iperf results at http://www.mikronauts.com/raspberry-pi/ ... -review/6/)

I was just pleasantly surprised at how noticeable the difference was at the desktop level - this was the first time I've tried to run one of these small SBC's off a hard drive.
Jim Manley wrote:
mikronauts wrote:It feels noticeably snappier for desktop use than running of an SD card, best guess is that the faster disk reads outweigh the slower seeks when loading large apps.
Pretty much any hard drive is going to be upwards of 50 ~ 100% faster than any SD card because the USB bus is capable of higher throughput than that of the SD card port due to limitation of the SD card port to only operating at 3.3 volts, not the 1.8 volts that highest-speed SD cards need to operate at their maximum transfer rate.

I assume you know that a USB 3.x interface/device is going to be wasted on the Pi because the USB bus on the Pi is limited to USB 2.0 speeds. If 3.x is all you have on a latest-technology device, it will operate at the slower rate, but a bunch of dollars will be circling the drain.

Re: FYI, RPi 2 runs nicely from USB hard drive

Posted: Sat Feb 28, 2015 9:47 pm
by markatlnk
I have 3 RPis all running 24/7 with USB hard drives. Two of them have the 3.0 hubs, not for the speed, but these (Anker) hubs have robust power supplies. One is a 512M B, another is the B+ and latest addition is the B2. I switched to hard drives after I crashed an SD card. I also flipped the swap space over to the hard drive and bumped it up to 4G. Not that I needed the space as much as a 1T hard drive has a bit more space than I needed. I did allow 50G for the OS partition and the rest was just for data. All are also running turbo mode to 1Ghz.

The B2 is fast enough to do development on and I do that regularly.

The only rule is to have fun with it.

Re: FYI, RPi 2 runs nicely from USB hard drive

Posted: Sat Feb 28, 2015 11:50 pm
by mikronauts
Thank you, good information.

I have one of my Pi's on an ORICO hub/power supply, works well. The others are mostly running off dc-dc converters or USB charger packs (robots).

This was the first time I tried running a Pi off a hard drive, but it definitely won't be the last.
markatlnk wrote:I have 3 RPis all running 24/7 with USB hard drives. Two of them have the 3.0 hubs, not for the speed, but these (Anker) hubs have robust power supplies. One is a 512M B, another is the B+ and latest addition is the B2. I switched to hard drives after I crashed an SD card. I also flipped the swap space over to the hard drive and bumped it up to 4G. Not that I needed the space as much as a 1T hard drive has a bit more space than I needed. I did allow 50G for the OS partition and the rest was just for data. All are also running turbo mode to 1Ghz.

The B2 is fast enough to do development on and I do that regularly.

The only rule is to have fun with it.