I’m referring to a server without a dedicated boot disk. This is not especially rare.
On an edge-style machine, you generally have a very limited number of M.2 slots, and dedicating one to a boot device uses up potentially 100% of your potential storage capacity, not to mention that an extra drive would be a non negligible fraction of total cost.
On modern servers, there may not be a usable SATA controller, and NVMe usually costs 4 PCIe lanes. Those aren’t free. You also end up paying the absurd OEM premium for an extra disk if you go with a big name OEM. Sadly, there is no industry standard cheap, reliable boot device standard, at least as far as I’ve ever seen. Maybe someone should push USB3 for this use case — the price is certainly right, and performance is likely just fine.
Server machines usually came with an SD-card slot on the board (and with ability to boot from it). This was often used for ESXi-like environments, which also required dedicated device for themselves.
There are also SATA-DOMs or USB-DOMs. You could use one of these modules with your machine.
is there a reason you can't just boot from usb? it sounds like the perfect match. I've built immutable bootsticks in the past that run in ram only (but with other distros). hetzner for instance lets you rent usb-sticks for their dedicated servers
FWIW, it’s been a little while since I’ve messed with the low-level details of BIOS/UEFI to kernel+united to USB root disk handoff, but I’m always slightly concerned that the system will mess up and hand off to the wrong device. For a system that uses USB for anything else, this opens up an attack/screwup vector in which the wrong disk gets used, leading to all manner of problems.
Also, an external dangly thing is asking for trouble (getting dislodged). An internal device solves this.
In any case, the Talos people seem to recognize this as a problem and are working on it.
On an edge-style machine, you generally have a very limited number of M.2 slots, and dedicating one to a boot device uses up potentially 100% of your potential storage capacity, not to mention that an extra drive would be a non negligible fraction of total cost.
On modern servers, there may not be a usable SATA controller, and NVMe usually costs 4 PCIe lanes. Those aren’t free. You also end up paying the absurd OEM premium for an extra disk if you go with a big name OEM. Sadly, there is no industry standard cheap, reliable boot device standard, at least as far as I’ve ever seen. Maybe someone should push USB3 for this use case — the price is certainly right, and performance is likely just fine.