Leaning towards Debian on a Raspberry Pi 400, any tips?

• Raspbian used to support better the hardware on Raspberries (esp. video decoding), although I believe Debian is catching up to that.
• Pop!_OS now has a Raspberry version, I tried that a few days ago and it's a nice desktop. Rocky (Alma too?) are also available.
• You can use USB SSDs, they really improve performance (for 50€ you can get half TB of nicer storage than a MicroSD). Depending on the Pi, you may need a MicroSD to chainload the USB- it's a minor time waste, but it's not really troublesome.
• Minor note, but I'll always bring it up. Prior to the Pi 5, no RTC clock. Minor issue, but some stuff doesn't handle that well (dnf needs-restart, notably).

About Debian as a desktop, I used that for ages- it's pretty good. The which distro thread might be better to discuss, though.

iljitsch said:

I'm about to pull the trigger on ordering a Raspberry Pi 400 as a system to do web dev testing, occasional light server duties, maybe some retro gaming from time to time, and running networking labs in Docker.


Any thoughts and tips appreciated.

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Obvious question is have you considered the wait/bare computer trade offs of waiting for a Pi 5 and getting a separate keyboard (or KVM)? That has provision for a RTC clock.

I'm periodically using a Pi 4 with Raspberry Pi OS as a desktop and it is OK, but there are times when I'd like a little more CPU - to give you a perspective it the bundled Chromium achieves ~4080 on https://mozilla.github.io/krakenbenchmark.mozilla.org/kraken-1.1/driver.html. You'd expect a Pi 5 to be somewhere below 2000.

Definitely consider migrating boot and / to a USB SSD once you've picked an OS, it is worth it for the application launch time benefits.

iljitsch said:

I gather that the Pi 5 uses a lot more power.

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When I looked, I didn't find that reported:

https://www.jeffgeerling.com/blog/2023/overclocking-and-underclocking-raspberry-pi-5 says 2.1W at idle for the 5.

The most recent firmware tested for the Pi4 at https://www.raspberrypi.com/news/thermal-testing-raspberry-pi-4/ is also listed as drawing 2.1W at idle. My Pi 4 with a keyboard and Logitech mouse dongle attached is idling at 3.1W.

From https://www.raspberrypi.com/news/introducing-raspberry-pi-5/ "The combination of a newer core, a higher clock speed, and a smaller process geometry yields a much faster Raspberry Pi, and one that consumes much less power for a given workload."

I can see the rationale if you don't want to wait for availability, or if you really want the integrated with the keyboard design, but I don't think power consumption is a well evidenced reason.

I'm making a point of this as I think performance of the Pi 4 is just about OK as a desktop, while the Pi 5 is likely to be enjoyably good enough.

iljitsch said:

One thing that I hate about the Pi 400 is the micro HDMI. Ideally, this would be USB-C/DisplayPort, but at the very last full size HDMI.

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I'd guess this is because the original intended use case was a spiritual successor to the BBC Micro which you could plug into a domestic TV so the early generations have full size HDMI.

They then wanted to offer dual display port (I think there's a significant demand for them as very thin clients) and were forced to micro HDMI for board space reasons.

Pi OS is just Debian with certain performance-oriented customizations for the Pi hardware and mission. The main repositories it pulls from are all Debian. You won't be using one of Debian's stock desktop environments (Pi OS just debuted a new one with a Wayland-specific compositor instead of OpenBox) but that's honestly not a biggie, underneath it all the basic concepts are the same.
As for slow flash drives, if you can give up one of the USB 3 ports then an NVMe drive in a flash adapter (or any external SSD, or a 2.5" on an adapter cable) will work much better than the microSD card as a boot drive. All the Pis since the 3 can boot from USB now.
To be honest, using the Pi as an introduction to Linux seems orthogonal to me. There's nothing special about Pi hardware except its limitations. If you want a Pi 400 just to play around with, you don't really need to invent another excuse than that. If you want to get used to "real" Debian there are much better options than a Pi. Any old spare box from 2010-ish with at least 4GB of RAM and sufficient drive space should work fine, and virtualizing is always an option for dabbling. But Debian on Pi hardware doesn't seem to offer any upsides that I can see.

Interesting thread.

I rather like the Pi 400s, granted I got them before any of the new stuff came out, but they are good for what they are, and self-contained.

As for alternative Linux distros for RPi tech, I have tried as many as I can (will write it up one day).

I settled on, Raspberry Pi OS lite just in case, but mostly Diet Pi and customized the install. The latter is very lean as initially it is a CLI, but XFCE can be added quickly from the menu system in 5 minutes.

SparkyLinux (Debian based) is experimenting with ARM based distros, and I really liked it when I tried it. Think of it as Debian having taken diet pills and tidied up. Looks like they are working on another release, soon.

The only gotchas with Diet Pi is plug any Pi 400 into the network via an RJ45 cable before the first few boots, etc then setup the Wireless via the menus, and best to install openssh-server. Their documentation is good and worth a read.

I found the best performance is to boot from quality, fast USB sticks and then having a separate user disk.

The links:

[The system is not letting me post the links to their sites, but Google/bing/Duckduckgo is your friend with that]

Enjoy!

My experience has been there's a lot of small but persistent and annoying problems trying to use Raspberry Pi for this stuff, and that the results are basically never appreciably better than if you just get the cheapest Atom-based miniPC you can find. Recent N95 or N100-based Celerons are actually pretty decent and offer vastly greater OS choice since they can run Windows, virtually any Linux distro, TrueNAS, whatever you like.

The problems I ran into mostly came down to: having to run very specific kernels, those specific kernels not being built with options that would be standard anywhere else (eg no ZFS support), and the lack in any existing RPI model of hardware encryption acceleration. Not sure if this will change in the 5 but it's a big problem for the 4 and earlier, and I guarantee you a random N100 PC will be easier to get than an RPI 5, and likely not even more expensive once you spec a realistic standalone PC config with a fan and case etc.

The 5 has "Broadcom BCM2712 2.4GHz quad-core 64-bit Arm Cortex-A76 CPU, with cryptography extensions" - https://www.raspberrypi.com/products/raspberry-pi-5/ .

RicDavis said:

The 5 has "Broadcom BCM2712 2.4GHz quad-core 64-bit Arm Cortex-A76 CPU, with cryptography extensions" - https://www.raspberrypi.com/products/raspberry-pi-5/ .

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That's good to hear. This was fatal to a bunch of the things I tried to do. Disk encryption and ssh connections were limited to <50 MB/s. ssh can be configured to use other ciphers like ChaCha20 rather than AES that do better without hardware acceleration, but disk encryption often can't. It's still enough of a pain to deal with the other random issues though that for the server, dev, and desktop use cases @iljitsch mentions I think they would be better served by inexpensive miniPCs.

With rpi's whatever the list price is, availability especially for a new version is always a pain, and stuff like case and fan is always extra, which gets it close enough to miniPCs that you're not really saving much and you are substantially worse off. Picked up a Beelink S12 recently and depending on spec that's as cheap as $125 on Amazon, which I am almost certain is competitive with a real world rpi 5 setup in price and vastly superior in performance and compatibility. Intel's latest E-cores are almost comparable to Skylake and about 2x the single thread performance of an A76 which is where a lot of things go from "it's ok I guess" and "this is unusably painful", especially with browsers.

I've done this more than once with various CPUs including rpi's, older versions of Intel's Atom/"Celeron" lineup, etc. Older Atom/Celeron stuff was pretty bad but still did better than RPI contemporaries due to the AES acceleration, but Alder Lake is where it pulls even with desktop CPUs from a few years ago and it stops being worthwhile to even bother with the tradeoffs. It's not worth touching ARM stuff unless you're getting a Mac or someone makes an ARM miniPC with ARM's X cores (or possibly if Qualcomm comes out with something interesting, but assume not until proven otherwise).

It's not just that the microSD cards themselves are slow (though there are slower cards). The reader in the Pis has historically not been fast.
This is one of many things being remedied somewhat in the new Pi 5, which nearly doubles microSD read and write speeds. But we haven't seen any indication of a "Pi 500" on the horizon.

My Pi 4 was excellent as a dedicated media server: silent, always-on, snappy enough to sling bits around the LAN. Makes my much more spacious and performant Synology seem sluggish due to the more aggressive sleep settings. Plus the Pi had no retina-burning blue LEDs. I had the headless Pi OS and ran Open Media Vault on top of that, as a My First NAS project. I also wanted to use it as a proof-of-concept for tiny, compact, off the shelf flash mass storage (thumb drives and microSD cards in USB readers crammed into every port) and it knocked all that out of the park, except I worried about waste heat cooking the flash chips. Didn't cause any noticeable problems for the year or so I had it running, despite the fact that they were always unpleasantly warm to the touch.

Wheels Of Confusion said:

It's not just that the microSD cards themselves are slow (though there are slower cards). The reader in the Pis has historically not been fast.
This is one of many things being remedied somewhat in the new Pi 5, which nearly doubles microSD read and write speeds. But we haven't seen any indication of a "Pi 500" on the horizon.

My Pi 4 was excellent as a dedicated media server: silent, always-on, snappy enough to sling bits around the LAN. Makes my much more spacious and performant Synology seem sluggish due to the more aggressive sleep settings. Plus the Pi had no retina-burning blue LEDs. I had the headless Pi OS and ran Open Media Vault on top of that, as a My First NAS project. I also wanted to use it as a proof-of-concept for tiny, compact, off the shelf flash mass storage (thumb drives and microSD cards in USB readers crammed into every port) and it knocked all that out of the park, except I worried about waste heat cooking the flash chips. Didn't cause any noticeable problems for the year or so I had it running, despite the fact that they were always unpleasantly warm to the touch.

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A 'Pi 500' with internal NVME slot(s) would be the perfect Pi for me. Fingers crossed.

Wheels Of Confusion said:

My Pi 4 was excellent as a dedicated media server: silent, always-on, snappy enough to sling bits around the LAN. Makes my much more spacious and performant Synology seem sluggish due to the more aggressive sleep settings. Plus the Pi had no retina-burning blue LEDs.

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There's an option in the settings of the three Synology units I have dealt with to turn those LEDs off.