Pi 4 and Pi 5 on shared SSD for redundancy

hi Bob,

My Pi4 was still running an the old operating system and i decided to purchase a new Pi 5 to make the system up to date. I also decided to run it on a SSD instead on the sd drive. That seems to work fine.

I’m just wondering now if I could use the Pi 4 as a redundant processor board and in case of disaster could it as simply to the production SSD hoping that the Pi 4 would boot as well and just continue replacing the Pi 5.

The Pi4 would be in shut down up to the point i need it.

Would that work? Want to have your opinion before just trying it and mess up things.

Not Bob here, but thought I’d throw in my .02.

The pi 4 and pi 5 have a major difference in that the 5 supports pci-e, where the 4 does not. The SSD you install is likely to utilize this functionality which means you would not be able to swap in the pi 4 in the event of a failure of the 5.

If this failure method is something you would like to prepare and account for, my recommendation would be to setup a backup job that would copy over the brewblox directory from the home directory of your pi 5 periodically. If the pi5 or SSD were to fail, you could install Rasberry Pi OS again, brewblox again, and restore your brewblox directory to bring back data and config.

Alternatively, abandon the pi altogether and run brewblox on more robust hardware. I’m running mine in a virtual machine on my esxi cluster with redundant hosts with redundant storage and redundant power. But that’s mostly because that server rack was already just sitting there producing heat anyway. :slight_smile:

There is absolutely nothing that says you couldn’t run it on an old, abandoned laptop as well. Built in UPS, even.

Hi John,

Thank you for your feedback! The situation on Pi 5 and PI4 is clear now.
I have to think it over what the better solution for me would be.
Starting with a crontask for making a snapshot of the system configuration will at least step 1.

Thanks