How do I attach two hard drives?

[antiseptic]

I have both RPI3 and RPI4. I had thought that I would have enough power with RPI4, but I guess not.

I have this thing:
https://www.newegg.com/p/1Z5-00NP-05M05 ... -_-Product

But it does not seem to work. I don't know if the correct module is loaded or not. I use Arch Linux. Is there something I should modprobe or pacman?

The only alternative I can think of, would be to buy yet another USB adapter, which I don't want to do.

[HawaiianPi]

The Pi3 and Pi4 can supply up to a max of 1.2A from their USB ports. That's for all 4 ports combined (with no per-port limits). Not enough to run 2 hard drives (probably enough for dual SSD). To run a pair of HDD you'll either need self-powered drives, or a powered USB hub.

[LTolledo]

On my RPi3B+ Raspbian Stretch Full Desktop, booting natively on Crucial BX500 SSD, sometimes I would boot it up (unknowingly) with a 2.5" 2TB Seagate HDD in Orico Clear SATA to USB3.0 HDD case-adapter (bus powered) still attached.

somehow it always booted.... just lucky perhaps...

and just to confirm... I tried it again a while ago
it did boot up (cold boot) from SSD, with a bus powered HDD (this time a 2.5" Samsung 750GB HDD) still attached (in Orico Black HDD case)
SSD on the left USB port, HDD and keyboard/mouse on the right USB port.
reboot also worked

me probably lucky with a non-RPF 5v 3.0A PSU (note: its NOT a charger!) powering the RPi3B+ setup....

[wildfire]

SSD & HDD != 2x HDD

[LTolledo]

Buster Desktop on RPi3B+, microSD boot
1TB Samsung HN-M101MBB HDD on one USB port
1TB Marshal MAL21000SA-T54 HDD on another port
Eluteng SATA to USB2.0 adapter (the original black) on both HDDs
5v 3.0A PSU (non-RPF official PSU)
and powering a 2-fan unit of Armorcase

Code: Select all

:~ $ lsblk
NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda           8:0    0 931.5G  0 disk 
└─sda1        8:1    0 931.5G  0 part /media/pi/USB1TB
sdb           8:16   0 931.5G  0 disk 
├─sdb1        8:17   0   5.5G  0 part 
├─sdb2        8:18   0   100M  0 part 
├─sdb3        8:19   0 175.5G  0 part /media/pi/W7TingSMS1TB54R200
└─sdb4        8:20   0 750.4G  0 part /media/pi/W7TingSMS1TB54R800
mmcblk0     179:0    0  28.9G  0 disk 
├─mmcblk0p1 179:1    0   256M  0 part /boot
└─mmcblk0p2 179:2    0  28.6G  0 part /

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~ $ sudo blkid
/dev/mmcblk0p1: LABEL_FATBOOT="boot" LABEL="boot" UUID="69D5-9B27" TYPE="vfat" PARTUUID="a8a9fec4-01"
/dev/mmcblk0p2: LABEL="rootfs" UUID="24eaa08b-10f2-49e0-8283-359f7eb1a0b6" TYPE="ext4" PARTUUID="a8a9fec4-02"
/dev/sda1: LABEL="USB1TB" UUID="01D4476EFD6AB330" TYPE="ntfs" PARTUUID="09af435d-01"
/dev/mmcblk0: PTUUID="a8a9fec4" PTTYPE="dos"
/dev/sdb1: LABEL="BIOS_RVY" UUID="562884DD2884BE0D" TYPE="ntfs" PARTUUID="279dc939-01"
/dev/sdb2: LABEL="System" UUID="DEEAB407EAB3DA4B" TYPE="ntfs" PARTUUID="279dc939-02"
/dev/sdb3: LABEL="W7TingMS1TB54R200" UUID="4C9CB8209CB8070C" TYPE="ntfs" PARTUUID="279dc939-03"
/dev/sdb4: LABEL="W7TingSMS1TB54R800" UUID="2E2A825A2A821EC9" TYPE="ntfs" PTTYPE="atari" PARTUUID="279dc939-04"

RPi3B+Buster2HDD.jpg (67.99 KiB) Viewed 739 times

maybe am doing something wrong here?
why is this even showing up?
there are 2xHDDs displayed in Raspbian....

[LTolledo]

tried it this time with the HDDs in the Orico HDD cases, and not using the Eluteng SATA to USB2.0 adapter

here are the results

Code: Select all

pi@RPi3BP1busterHDD:~ $ lsusb
Bus 001 Device 008: ID 2537:1066  
Bus 001 Device 006: ID 046d:c534 Logitech, Inc. Unifying Receiver
Bus 001 Device 004: ID 1a86:8074 QinHeng Electronics 
Bus 001 Device 009: ID 152d:0578 JMicron Technology Corp. / JMicron USA Technology Corp. JMS567 SATA 6Gb/s bridge
Bus 001 Device 005: ID 0424:7800 Standard Microsystems Corp. 
Bus 001 Device 003: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 002: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
pi@RPi3BP1busterHDD:~ $ lsblk
NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda           8:0    0 931.5G  0 disk 
├─sda1        8:1    0   5.5G  0 part 
├─sda2        8:2    0   100M  0 part 
├─sda3        8:3    0 175.5G  0 part /media/pi/W7TingSMS1TB54R200
└─sda4        8:4    0 750.4G  0 part /media/pi/W7TingSMS1TB54R800
sdb           8:16   0 931.5G  0 disk 
└─sdb1        8:17   0 931.5G  0 part /media/pi/USB1TB
mmcblk0     179:0    0  28.9G  0 disk 
├─mmcblk0p1 179:1    0   256M  0 part /boot
└─mmcblk0p2 179:2    0  28.6G  0 part /
pi@RPi3BP1busterHDD:~ $ sudo blkid
/dev/mmcblk0p1: LABEL_FATBOOT="boot" LABEL="boot" UUID="69D5-9B27" TYPE="vfat" PARTUUID="a8a9fec4-01"
/dev/mmcblk0p2: LABEL="rootfs" UUID="24eaa08b-10f2-49e0-8283-359f7eb1a0b6" TYPE="ext4" PARTUUID="a8a9fec4-02"
/dev/mmcblk0: PTUUID="a8a9fec4" PTTYPE="dos"
/dev/sda1: LABEL="BIOS_RVY" UUID="562884DD2884BE0D" TYPE="ntfs" PARTUUID="279dc939-01"
/dev/sda2: LABEL="System" UUID="DEEAB407EAB3DA4B" TYPE="ntfs" PARTUUID="279dc939-02"
/dev/sda3: LABEL="W7TingSMS1TB54R200" UUID="4C9CB8209CB8070C" TYPE="ntfs" PARTUUID="279dc939-03"
/dev/sda4: LABEL="W7TingSMS1TB54R800" UUID="2E2A825A2A821EC9" TYPE="ntfs" PTTYPE="atari" PARTUUID="279dc939-04"
/dev/sdb1: LABEL="USB1TB" UUID="01D4476EFD6AB330" TYPE="ntfs" PARTUUID="09af435d-01"
pi@RPi3BP1busterHDD:~ $ 

[HawaiianPi]

Like all things, computer SSD and HDD vary in power consumption. Some will be better than others, and SSD should be lower power than HDD, but I have seen some SSD rated for 1A and HDD rated for 500mA, so YMMV.

In my experience, USB HDD typically exceed the USB 2.0 500mA power spec, but are close enough that they often work. However, the Pi 3B/3B+ computers do not follow the USB 2.0 power spec (which would require 2A total at the 4xUSB 2.0 ports), so they tend to struggle with more than one HDD. But I was making a generalization above when I said it would not work.

If you have two USB HDD that are exceptionally lean on power, then sure it could work. That doesn't mean I would recommend it, or even suggest it's a good idea. I've posted previously that I was able to spin up and mount dual HDD, but I still said you should use self-powered drives or a powered hub for best reliability.


@ LTolledo,
Have you tried a large file copy operation between the two HDD, or configuring them as a RAID?

[King Dub Dub]

The Pi3 and Pi4 can supply up to a max of 1.2A from their USB ports.

But that has to be changed in the config.txt, and antiseptic hasn't mentioned doing that yet.

If you want to, get the full commented config.txt from https://github.com/Evilpaul/RPi-config/ ... config.txt
Open it and find the section labled "USB Power", then uncomment "max_usb_current=0" and set 0 to 1.
OR
Just go into your default config.txt and copypasta "max_usb_current=1" into it, and maybe
mark it with your own comment so you remember that you changed it. Good Luck!

[emma1997]

As mentioned in earlier posts I've had no problem hooking up 3 WD 2t Elements and either a Team 240g or kb/mouse dongle to a Pi4. Initially power source was an issue but using 12v w/buck modules like in the photo I posted some weeks back solved it. I've had several installations running like this last few years and a few friends and apparently forum members too.

Not all of these chinese modules work with so many extra attachments. The little 5/$1.00 ones (rated 3a but barely do even an amp) are enough for one drive. However the so called 5a (2a real) versions can handle at least 3 drives. Actual testing shows the cheapie modules only continuously capable of about half their rating. More than enough in my Pi setups though which are milliamp range and rarely amps.

Total lack of 5v power cabling is also an important advantage of my method. Maybe HD brand matters too but I found a few other modern 'portable' brands also work ok in 3s. I couple old models did fail but those were the ones that needed double USB anway,

[Samuel32]

I would not have expected 2 drives to work at all.
The max_usb setting only applies to B+ and 2B models Official Site. The max current setup (1.2A) is default on the 3B.
Do the drive USB connectors touch or interfere with each other when in the same stack?
Do you have the same problem when booting from a cold start vs hot-plugging the drives after boot?

[LTolledo]

@ LTolledo,
Have you tried a large file copy operation between the two HDD, or configuring them as a RAID?

Nope, didn't tried it when I posted it, as I needed to "recharge my internal batteries"

Did tried some file copy later on... a single 500MB file from a network share to each HDD, and it did copy successfully
but coping between the two drives failed, as the drives "ejected" themselves, only to return back again a few seconds later

if copying smaller files (anything below 15MB) you'll probably get away with it, bigger than that and the drives "eject" themselves.

so the conclusion here
Yes you can attach 2 bus powered hard drives, if you really want to attach 2 bus powered hard drives
Yes you can copy large files to any one of the two bus powered hard drives, as long as you do the copy 1 drive at a time...
No you cannot copy large files between the 2 attached bus powered hard drives, but "may be able" to copy if the file size is less than 15MB.

However.....
you can attach 2 (or more*) self powered hard drives (which is a better choice), or 2 (or more*) bus powered hard drives connected to a "RPi compatible" powered USB hub. (note here: not all USB powered hubs work with the RPi)
you will be able to copy large files between the two (or more) attached hard drives (as long as those are self powered or connected to a powered USB hub)
you'll need to wrestle with tidying the wiring of the power for the RPi and the self powered devices...

* depends on RPi board.

...and then there is this somebody who blurted out "....just attach the two hard drives to the RPi using hot glue... no problem...!"

[emma1997]

Do you have the same problem when booting from a cold start vs hot-plugging the drives after boot?

Items like big SSD and older HD sometimes cause an already loaded Pi to reboot so I try to avoid hot-plugging generally. Rarely a need so why risk unless absolutely necessary?

These drives only draw current for a few milliseconds during spin-up. Once running draw relatively little. I think most models sense volt drop or current and sequence their startup if on the same bus. I know my WD take twice as long when all plugged in together.

Physical interference of all the Pi connectors not just USB has been a big annoyance. Specially when bulky adapters are involved. Fortunately extender cables are cheap from China and almost always work. The USB3 ones that come with the portable drives do not interfere.