[chbot] [OT] SSD for a Pi 400.

Chris Hellyar chris at trash.co.nz
Sun Jan 24 03:00:47 GMT 2021

Hi Volker..

These are the ones I'm using:


They do support full smart functionality.

There is a long thread somewhere on the RPi forums about which adapters 
work, but my google-foo is letting me down at the moment.

The ones that didn't boot reliably for me were Orico (The clear plastic 
external enclosures) and ones shucked from Seagate enclosures.  They 
worked fine as just an attached disk, but will not boot reliably on the 
Pi4, even though they work Ok on the PI3 using the 'bootcode.bin' 
broadcom bootloader.

The other issue I've had is under-voltage warnings with some SSDs, FYI...

The Pi 4 is only good for 1.2A combined on all four USB ports and some 
SSD's peak over that.  The disks I've had problems with there were 
Samsung EVO 850's and an Adata SP900.  With the Kingson A400 I'm running 
the 120G for boot and a 5400rpm 1TB shucked Seagate one one of the pis 
with no under voltage warnings.  I'm powering my Pi's directly from the 
GPIO pins from a 450W ATX PSU as well which helps, running off the USB C 
I've never had a two-disk setup work reliably.  Up side is more usable 
power, down side no polyfuse / protection so if you're going to take 
that path you should know what you're doing...

The Pi 4 fixes the single-bus issue.  The Ethernet and USB (2x3 and 2x2 
on the Pi4) are now on separate PCI lanes.  Using a Pi4 as a NAS you can 
saturate the Gigabit NIC from an SSD connected to the USB3 even running 
ZFS or BTRfs which can both be a pig over USB.  (Can't recommend BTRfs 
on Pi4/USB though, had some weird there, switched to Ubuntu 64bit to get 
ZFS, no issues so far, touch wood)

That Transcend disk is a good price but I was looking for SSD's I could 
use in other places if my pi-cluster didn't work out. :-) As it happens 
the 4xPi4 Cluster is has made a very usable replacement for a SFF i7 
desktop that was running VMs / containers which gives me a meaningful 
power saving so now I'm looking at building it a cute custom case as 
well. :-)

- Chris H.

On 24/01/21 2:16 pm, Volker Kuhlmann wrote:
>> Just be aware that some USB adaptors will not mass-storage boot on
>> the Pi4..  Pretty much anything works on the Pi3 from my messing
>> around over the last couple of years.
> Could you say which Startech adapters you tested? Or do you think
> they're all the same wrt booting and throughput?
> Would you mind checking whether those adapters are SMART compatible? Run
> smartctl -a /dev/... and if you get full output as on a desktop
> computer, the anwser is yes.
> The "Transcend ESD230C 240GB USB" doesn't seem a bad deal at $70,
> Kingston A400 120GB $40 + Startech adapter $30 so same price for half
> the volume.
> Could the person with the Transcend on RPi please check the SMART status
> as per above and post whether it gives SMART output or and error/drivel?
> Ta.
> Traditionally, RPi bandwidth was shared between internal (micro)SD card
> (internally USB connected), Ethernet interface (internally USB
> connected), and all USB2.0 ports on the board (aka PPP - piss poor
> performance), so connecting external storage was basically pointless.
> Which RPis actually bust that limit?
> Volker

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