If you have a Raspberry Pi, you normally have to deal with a micro SD card. Hans Man investigated another solution with an SSD and also used a SATA USB cable.
Hans Man
After working with the Raspberry Pi for some time, you run into it: the micro SD card is not as robust as you thought. This usually happens when you’ve already installed a lot of software and got it up and running with some effort. Somewhere in the back of your mind the importance of a backup still gnaws, but “that will come tomorrow”. And at that moment the micro-sd card starts to sputter. Sometimes one or more software applications stop working (properly), but it can also happen that the Pi just stops completely. Unless you’ve made that backup anyway, there’s nothing left to do but format the card and reinstall everything.
FROM SSD
But there is another way. What if you could start the Raspberry Pi from a solid state disk or SSD? SSDs are getting cheaper by the day and they are much more stable than most microSD cards. An additional advantage is that they are also much faster.
The SSD I’m using has a SATA interface, which is an elongated connector. However, the Raspberry Pi has USB connections and to connect the two, you need a SATA/USB cable. So much for the simple part.
SATA/USB CABLES
The Raspberry Pi does not just start up with any SATA/USB cable. Some models work, some don’t. This has to do with the chipset used on the SATA/USB adapter. If you don’t know what to look for, you run the risk of buying an adapter that just won’t work with the Raspberry Pi. The good news is that you don’t have to throw it away, you can always use it to connect an old hard disk or SSD to your laptop: that usually works.
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| Please note, all information comes from the seller’s website |
To test which adapters can and which cannot be used with the Raspberry Pi, I have collected a handful of different ones, of which you will see an overview below. As far as possible I have also mentioned the seller and the price at the time. You can also see which chipset is in it according to the seller. Note: this is not always correct!
RASPBERRY PI 4B
For the tests I used my Raspberry Pi 4B with 4 GB, powered by an original Raspberry power supply (2.5A). The latter is important, because the SSD is powered from the USB port and the power supply of the Raspberry Pi must provide sufficient power for this. The USB ports of this Raspberry Pi can together deliver 1.2 amps, with no limit per port. The SSD I used for the test is an old Kingston with 30 GB with a power requirement of 0.4 amps.
That’s not much: the Samsung EVO 870 250 GB that I normally use for my home automation server draws a whopping 1.1 amps, so almost three times as much! To keep all adapters apart, I numbered them from 1 to 7.
VERSIONS
If we look at the versions, there are some differences. For example, adapter number 2 is a normal cable, with a SATA and a USB plug. Numbers 1 and 3 are also cables, but now with a double USB plug. This is useful if you want to connect a ‘heavy’ disk to, for example, your laptop, where a maximum of 0.5 amps can be supplied per USB port. The double plug allows you to feed the disk twice 0.5 amps. For the Raspberry Pi, this is not so relevant.
The other adapters are flat boxes, in which you can neatly build the SSD. Usually that is quite simple: cover off, disk in, cover back on. Only with adapter number 5 the disk is secured with small screws.
The connection between the boxes and the Raspberry Pi is made with a special cable: the well-known USB plug at one end, and a special flat plug at the other end. And here too number 5 is an exception: the cable is equipped with a USB 3.0 plug at both ends.
MEASUREMENTS
For the measurements I provided the Kingston SSD with a standard Raspbian operating system. As the only application I have installed Agnostics. This allows me to measure the performance of the disk quite simply.
I also provided the Raspberry Pi with the latest updates in advance, and enabled Boot from USB. How this should be done, I will not consider here, there is enough information about this on the internet.
For each adapter I took two measurements: once connected to a USB 2.0 port and once connected to a USB 3.0 port. After starting the Raspberry Pi I checked with the command lsusb the connected USB equipment to see whether the chipset indicated by the supplier is correct. Then I did a speed measurement with Agnostics. I performed each measurement three times, after which an arithmetic average was determined. For each measurement I note: sequential write, random write and random read.
RESULTS 
The following table shows the results. Because adapters 1, 4 and 5 just didn’t work (the Raspberry Pi gave “kernel not syncing”), I have omitted these numbers from the table. For the observant reader: a stowaway has indeed crept in: number 8.
I wanted to show that although there are differences in the adapters, the numbers show that those differences are not huge. What does matter is the performance of the SSD used. In measurements No. 7 and No. 8, I used the Ugreen USB 3.1 adapter. For measurement no. 7 it is equipped with the Kingston SSD, in measurement 8 I used my more modern Samsung EVO 870 250 GB. And here the age is clearly visible: the EVO runs in circles around its opponent, especially on USB 3.0 it is a true speed monster.
What is striking is that all adapters with random write show better grades than at random read, only the EVO does that very differently: here is random read significantly better than write. I don’t know why that is, it could be something with caching may have to do with it, but that’s speculation.
CONCLUSION
The figures show that the different adapters do not differ much from each other. The choice is actually determined in a few simple steps: do you want to connect a separate disk to the Raspberry Pi with a cable? Or do you want a nice cabinet in which the disk is safely stored?
And of course the most important factor is the chipset: choose one that works! Or make sure you can return the adapter if it doesn’t work. Based on the quality of the housing, the cable and the performance, I would choose the Ugreen USB 3.1 myself. Even the packaging is neatly taken care of.
Based on this whole: five stars for this SATA/USB adapter.