raspberry-pi-pcie-devices

I documented everything in excruciating detail in this GitHub issue [1] — but in summary it was RAID5 created by mdadm (to replicate what the Drivestor 4 Pro does via ADM—it doesn't have ZFS as an option), and bcache set up on top of that with an EXT4 filesystem. [1] https://github.com/geerlingguy/raspberry-pi-pcie-devices/iss...

The Raspberry Pi does not support PCIe I/O BAR space. That's not a hard requirement to run a modern GPU as far as I know, but drivers do kind of assume it's available. In particular, VBIOS stuff often needs it. The message from the Radeon driver is not a hard error, but presumably other things break as a result. The Broadcom SoCs used on Pis still suck, and although this can probably be made to work, someone familiar with this codebase needs to care enough to fix the drivers to make it happen. It's probably quite doable for the open source drivers, but I wouldn't expect Nvidia's blob to work any time soon unless they take the time to fix it. Not all PCIe root ports are equal. Some are, shall we say, less than amenable to devices more complicated than a USB controller. Looking through the discussion here, there is some rather concerning st

There are a few people currently working on NAS boards based on the CM4. A few different approaches in terms of chipsets used and performance targets. I'm trying to track them in this GitHub issue [1] but a couple people have remained more or less anonymous as they don't want to attract attention too early. The single PCIe lane is the biggest limitation if you're looking for raw speed (350 MB/sec is kind of the upper real-world sustained transfer limit), though since the gigabit Ethernet port is on a different interface, you can still expect to get 80-100 MB/sec network transfer speeds. Something like this, with the right case and OMV or other adequate software would be a relatively competitive replacement for low-end NASes. I'm also exploring building a 2.5G NAS with a CM4, but the PCIe bus speed limitation is what kinda hamstrings that.