Best February 2020 Rachel Pi deployment solution

Visiting Ghana again and want to take out some more Rachel Pi cards. The current system used in Bolgatanga is the jamesk version available at end of Jan2019 booting directly off a small 64Gb sandisk usb. What version should I take out this year and why? I have received an email to say that Ka-lite is going to no longer be supported so I guess I should probably help them to move to Kolibri.

Will probably stick with 3B+ machine as the Pi4 seems less deployment ready/flexible in a remote location context - really like the usb booting solution. That said I will take out a Pi4 and boot off sd and store downloads etc on ssd if this is consodered a good foward looking solution. Ideally I would like Rachel on a sandisk ssd that I can just plug in to any usb bootable Pi.

Hi @TrevorG,

Not much changed between the Raspbian Stretch images and the Raspbian Buster image from a user standpoint. All of the same content is available. There were updates to the system and it’s services with some minor user interface changes, but it’s still the same user experience. The main change was support for the Raspberry Pi 4 in Buster.

There is one bug within some versions of Buster that was causing Kiwix ( Wikipedia module support ) to not start every time and while I didn’t see it with the image I released, it was there at some point if Buster was updated from the terminal. It’s fixed now and there’s a note in the RACHEL-Pi downloads page on how to fix it if encountered, but it’s something to think about. In my opinion the Raspberry Pi4/Buster rollout has been anything but smooth and it would be good to wait until it’s more stable and with USB support before deployment. They have released some updates that have fixed the heat and other issues, but they’re still considered experimental. Once they’re stable and there’s a new image available at I generally make new images.

KA-Lite hasn’t been updated in a long time while Kolibri is in active development. I would start with Kolibri as KA-Lite is considered a legacy project now. While you could run both at the same time, it’s better to choose one to save on system resources.

So I would say it’s between the Stretch or Buster Kolibri images and the choice is down to whether or not you use an SSD or USB with Stretch or an SD card with Buster. The two people with the most experience in deploying RACHEL-Pi that I’ve seen are @giakonda and @SHOMI. They’ve been kind enough to share that experience with other users so maybe they’ll answer any questions you have and can comment on stability. I know that @SHOMI has used SSDs with the stretch images.


TrevorG ,

I am using Jamesk RACHEL PI Stretch image from either late 2018 or Jan 2019, I just can’t recall at the moment. So far, I have about 96Gb loaded on the SSD and from the classes we have had, it still boots and performs well. I am still using the KA-Lite though. I am looking at Kolibri which will be another new step for the teacher to get used to. With the SSD’s being cheap, I have several that are exact duplicates just in case of failure or corruption. The need to upgrade is not an immediate concern, but easy enough to do at home and swap out on a future trip.

I loaded jamesk PI4 image to a microsd last year and as of 1/17/2020 it had been up for 176 days with a temperature of 35C in a C4 Labs case with fan. I had periodically downloaded a new module, pulled up videos and books without any issue, but I did notice that the Kolibri module stopped responding at some point, but restored after I rebooted it Friday 1/17/20.

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Thanks James. I have downloaded your 20-09-2019 image and am starting to get to grips with Kolibri. The most immediate thing I like is the ability to just download specifically what you want and in manageable download sizes e.g. parts of Khan and then more later. I am running the 29-09-19 image off a 64gb sandisk usb on a RPi 3B+. Seems to be working fine. I think I will take out some 3B+ machines with me when I go to Ghana in February. I think I will use a sandisk ssd 250gb instead of the usb.

Thanks again for your help, and of course for the image updates etc

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Thanks for your comments Shomi. The experience we have had in Ghana is that the sd cards (full size and micro) have been very resilient in what is generally a very hot and dusty environment. I am going to take out RPi3b+ machines probably booting off a sandisk ssd. I will also take one RPi4 as a ‘try out’. Are you running everything off the micro sd for the RP4 ie booting and downloaded Rachel data?

Have you seen any speed or number of connections benefits with the RPi4 compared with the RPi3B+?

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I am just using the PI4 with a 64Gb microsd at home to check out. I had not connected any USB drives to it. I have not had the chance to test the number of connections with the PI4 .vs PI3B+.

The 3B+ server is just running on a Micro Center Inalnd 120Gb SSD in one of their aluminum enclosures. The 3B+ desktops are all using 32Gb microsd’s.

It is hot in Haiti and that’s always a concern as to how hot will it get. I have the desktop PI’s in a C4 Labs 6 port bramble box with 3 fans on the back to move a little air.

Good luck on your trip.

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We have been using RACHEL on Raspberry Pi4 with 128Gb SD cards for about 4 months. We sent 17 of them to schools without grid power along with 20Ah power banks, the sort you might take with you if you wanted to keep you phone charged. So far the only issue we have had is from people logging in with Admin rather than admin as their username. There has been no issue with the heat. I have not yet tried the bios upgrade on a RACHEL Pi4 but there was no issue with the desktop version.
sudo apt update
sudo apt full-upgrade
This fixes the heat issue.
We have used Kolibri for almost a year, it does present some training issues but we now have several teachers who know how to manage classes but even they prefer to use classroom teaching with a large screen because of the lack of individual machines for the kids.
Next month we are going to create a cluster of 5 Raspberry Pi 4s in Bbakasa school. We will power the cluster with 4x350watt solar panels and 4x250Ah batteries. I’ll let you know how it goes. So far the biggest issue is keeping the batteries safe and well maintained. I can’t wait for the LiFePO4 batteries to drop in price.

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Thanks for this Giakonda. I guess as a Rachel server booting off the sd card the usb 3 and 2 ports are effectively redundant on the 4B4 (assume 4Gb version being used) ie just sd and power into the 4B4.

What benefits do you see with the 4B4 as a Rachel server compared with the 3B+?

On Kolibri, what content has proved to be most useful for your teachers? Lots is available on Kolibri but at risk of downloading too much and ‘not seeing wood for the trees’. Are you adding local content e.g. uploading pdf files of say IT curriculum onto the Kolibri versions of Rachel?

All credit to you for the work done in powering the systems using solar/battery storage.

The USB3 port was a really exciting feature of the Pi4 release, but without USB booting support they are pretty well useless for RACHEL-Pi. The current official RACHEL code base doesn’t have USB module loading support and all of the images that I have released so far have just been getting the official code working with the latest operating systems/devices.

I have developed USB module loading separately from that code base as well as other features, modules, UI updates, and admin interface changes. USB module loading works in my testing with Pi4 and the USB3 ports, but I’m not really sure how to proceed. Anything I release at this point isn’t part of the official RACHEL code, but the official code hasn’t really changed so any new official images will basically be the same.

Thanks for this James. It seems to me best to wait until usb booting support is available on Pi4. Then Rachel could be installed on an ssd which is just plugged into one of the usb3 ports. This would provide a simple deployment solution of Pi4, ssd and power chargers. If the Pi4 fails for any reason, then it would just be a swap to another Pi4. Guess this deployment architecture works today with a 3B+ but via usb2 and only 1Mb memory on the Pi.

You’re welcome Trevor. It sounds like both @SHOMI and @Giakonda have had success with the Pi 4 with a MicroSD, but if you’re set on using an SSD the 3B+ is the highest supported model.

This post is a good comparison of the features of each device and it seems the Pi4 beats out the 3B+ in every aspect. Without real world testing and watching the resouce usages with something like htop or top, I’m not entirely sure an SSD over USB2 is any better than a high speed MicroSD on the Pi4 or if more RAM makes much of a difference. Whatever you decide to go with, it’s always best to have backup options in case one fails due to an improper shutdown or something else. MicroSD cards are popular for that since they’re cheap and so small it’s easy to ship them.


Most used by teachers in Siavonga are the Kolibri African Story books, They are in Tonga Nyanga and Bembe.
Also popular are the CK 12 books, Hesperian Health guides Practical Action and the Teacher training module.

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Hi Giakonda.
In a recent blog you mentioned Zambian language books on Rachel Pi can these be loaded on a Rachel server based platform and if so where can I get them. Looking forward to your reply.
Pat Bergin - Propel Education supporting Linda Community School, Lusaka

I get them from kolibri, log into your pi with a browser as usual. I guess you use as the IP address. but instead use
This gives you access to kolibri
you will have to setup kolibri if you haven’t already done that.
I have some notes on kolibri on

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I hope to be in Lusaka/Siavonga towards the end of February if you would like to meet up

Update on my February Rachel Pi deployment. I downloaded the Jamesk buster version of 29-09-2019 and installed this on a 64 Gb usb device which I then used on a 3B+ to download about 57Gb of content - OER2GO and Kolibri modules. All working great. I have ‘cloned’ the 64Gb usb onto a 128Gb sd card using dd. The sd card is now working fine on my newly acquired 4B4. The only issues I have are:

(a) I cannot seem to be able to measure the temperature of the 4B4. Bash will not recognise vcgencmd measure_temp
(b) my sd card shows up as only have the same spare space as the 64 Gb usb i.e. not the additional space that I want from the 128Gb card. How do I extend the space available for additional Rachel modules?

The 4B4 does seem to enable content to be displayed a bit quicker, but I am not ‘blown away’ in making a comparison with the 3B+.

Glad it’s working. These should be the solutions

a) I think it’s possible the /opt/vc folder is missing or the command alias is. You can try running the full path, “/opt/vc/bin/vcgencmd measure_temp” instead and see if it runs. If it doesn’t you can run “sudo rpi-update” and it should be restored on reboot.

b) You will need to run “sudo raspi-config” and run “extend filesystem” to take up the entire space. The RACHEL-Pi images automatically resize the file system on the first boot, but it only happens the first time. If you’ve cloned a smaller card to a larger card that’s already been run once you’ll have to resize manually.

There are a few things that the Pi4B has that should improve the performance but without USB boot the MicroSD bottleneck is still there. It’s definitely faster for me during development and testing, but serving content requires reading off of the storage device.


Thanks James. So clear and so quick to implement. Now all working fine. I did initially have some difficultly with the sudo rip-update. Got !!!failed messages about ca-certificates and time not being set correctly. Unplugged everything. Plugged it all back in again. Tried again and it worked.

I have seen a James Chambers tutorial on booting the 4B4 from the usb drives. I am going to follow this and see if I can get Rachel running this way. I hope the benefit would be c. 300 MBS upload speeds?

You’re welcome Trevor. I’m interested in the results of your USB test. That method is very picky with devices so I haven’t considered it an official option. It would be nice to know what speeds RACHEL-Pi on a Pi4B should be capable of though.

Followed the set of instructions from James A Chambers and everything works fine. The only issue is I have used the Raspbian Buster image from 26-09-2019 instead of your Rachel image!!! Do it all again tomorrow with the right image!

As feedback on the process setout by James A Chambers, it was very straightforward to follow and apply. I have used a Sandisk Extreme portable 250Gb SSD.