Usb 3.0 ports and powering 2 hdd

I have two 2.5" HDDs connected to both Ten64’s USB 3.0 ports.

From time to time you can hear characteristic click - either not enough power or bad HDD from my experience. Also I/O errors in the logs.

After connecting the HDDs to my desktop machine, the same layout for the disks (cryptsetup+btrfs+raid1), no issue when writing 100 GB of data.

I am using the original power supply I received with Ten64, so that should give enough power, I believe. I am running my CPU at 1.2 GHZ / 0.9 V.

Also, there is LTE card in the M.2 key B slot (can be relevant judging by the Ten64 components diagram).

Is it possible to have two drives connected to USB 3.0 ports or is this idea doomed from the start?

There are 1.5A-rated (2.0A peak) protection switches on each USB port (that is, each port has it’s own limiter)
Is it possible your HDDs are exceeding this limit?

If the devices are exceeding the current limit (and having their power cut off) this should be reported in the kernel log

The labels on the HDDs say 5V / 0.39A.

Which USB 3.0 port (upper or lower) is shared with M.2 key B slot? I can attach just one drive to it and see if the problem persists.

Lower port → direct to CPU
Upper port → via USB hub

@mcbridematt Thanks for the information.

I have done multiple tests. The problem is USB port independent (other factors ruled out as well), and it applies to one disk only when the two disks are attached.

One of “the same” WDC disks I received, the one affected, is older model. I would not trust this setup at this stage, so will replace the disk, and take it from there.