Progress as of 24 December 2019

This is where Marks Rpi Cluster was on Christmas eve 2019. A total credit of 7,349,000 and a rather low average of 3,824 per day. The hot weather mixed with smoke pollution from the bush fires has kept the cluster idling.


Cluster nodes
Marks Rpi Cluster is ending 2019 with the following configuration:
10 x Pi3 model B+ compute nodes
10 x Pi3 model B compute nodes
2 x Pi4 model B (4GB) compute nodes
2 x Pi4 model B (2GB) support nodes


Other news
I have two Pi4's crunching for the farm (replacing a couple of Pi3's). The Pimoroni fan shim's that are cooling them are making noises from time to time so I can't see them lasting too long.

I still haven't managed to find a place that can provide a custom power supply capable of powering 4 Pi's. While I can find a bare-bones power supply it still needs wiring for the USB type C plugs, a fan header as well as needing a case.


2020 plans
I hope to replace all the compute nodes with Pi4 model B's. They're about 33% faster than the Pi3's and have more memory which makes them more flexible for future compute tasks.

Sort out the power supply situation which may require me to create a 3D printed case for the bare-bones power supplies.

Switch to 64 bit mode (aarch64) on the Pi4's. The current farm is running 32 bit (armhf).

Add buster-backports to a Raspberry Pi

Lets assume you wanted some app from buster-backports, usually because its more up to date than the version in buster. The Raspberry Pi foundation doesn't have a backports repo so you have to use the Debian one instead. This is how to add it.

Update: March 2021

The Raspberry Pi OS 64 bit already has the necessary signing keys. I haven't used the 32 bit one for a while but it may also have the necessary signing keys. You only need to do point 2 if you get an error telling you you don't have the GPG keys.

As mentioned in the comments the GPG keyservers disappear. The kfwebs.net listed below is no longer available but there are others listed in the comments that can be used instead.

 

1. Add to /etc/apt/sources.list
This adds the Debian buster-backports repo to our list of repositories to use. To edit the list of repositories:

sudo nano /etc/apt/sources.list

Add the following line to the end

deb http://deb.debian.org/debian buster-backports main


2. Add Debian Buster keys
This adds the signing keys so we can trust the Debian repos.

gpg --keyserver hkp://keys2.kfwebs.net:80 --recv-keys 04EE7237B7D453EC
gpg --keyserver hkp://keys2.kfwebs.net:80 --recv-keys 648ACFD622F3D138

gpg --export 04EE7237B7D453EC | sudo apt-key add -
gpg --export 648ACFD622F3D138 | sudo apt-key add -


3. Tell apt to update
Tell apt to get the latest list of packages.

sudo apt update


4. See if there is an updated package
If you want to see if there is an updated package called xxx use the following command:

sudo apt list xxx -a


5. Get a package from the backports repo
By default apt won't install packages from the backports repo, you need to tell it. If we want to install package xxx from buster-backports use the following command:

sudo apt install -t buster-backports xxx

ARM64 on Raspberry Pi 4

It doesn't work. Well bits of it do. If you have got an up to date kernel, I am on 4.19.75, you can simply put it into 64 bit mode by adding "arm_64bit=1" (without the quotes) to the end of /boot/config.txt and reboot it. The kernel will now be an aarch64 kernel.

The Raspberry Pi foundation doesn’t currently have an arm64 repository so all of the programs are 32 bit (armhf) apart from the kernel. I had BOINC installed from the foundation repo (ie armhf version) and then switched the kernel to 64 bit mode and it continued to work. Not everything will. I wanted to get the arm64 version of BOINC. It kept choosing the foundation repo. I tried specifying I wanted the 64 bit version and it complained about dependencies. I commented out the foundation repos so it only knew about Debian and then I removed the armhf version of BOINC and tried installing the 64 bit version - it still complained. In the end I gave up.

My next step will be to try a 64 bit Ubuntu on it. Until then I have put it back to 32 bit mode and reinstalled the armhf apps.

Starting with Pi4 model B

In the last fortnight I ordered another two Pi4 model B's. The 2GB version this time. I already had two of the 4GB versions, one as a proxy server and one as a storage server. I swapped them around so they became 2GB devices, they don't need large amounts of memory.

I used a different supplier this time as they had the Pimoroni fan shim. My regular supplier (Element 14) doesn't seem to carry the fan shim. I have put one on a 4GB Pi4 compute node. While crunching I am seeing temps of 50-51 degrees C on the Pi4B with the fan shim and the top of the case off. The room temperature is 28 degrees C.

The idea is to run a few Einstein BRP4 work units through using armhf (32 bit mode) to get timings and then I will switch it to 64 bit mode and try it again. Current work units, running 4 at a time under the armhf architecture, are estimated around 7 hours on the Pi4. It hasn't finished yet. The Pi3B+'s have been taking a bit over 11 hours and the Pi3B's have been around 11 and 1/2 hours.

There isn't a project supplied arm64 app but there is an optimised arm64 app available. We're hoping to get the Einstein project to accept the arm64 app seeing as they don't currently have one.

Another reason for switching to the arm64 (otherwise known as aarch64) architecture it that there is an experimental Einstein FGRP app for it. It needs around 1GB of memory per work unit so a 4GB Pi4 will be required to run it on all four cores.