I am planning to build a multipurpose home server. It will be a NAS, virtualization host, and have the typical selfhosted services. I want all of these services to have high uptime and be protected from power surges/balckouts, so I will put my server on a UPS.
I also want to run an LLM server on this machine, so I plan to add one or more GPUs and pass them through to a VM. I do not care about high uptime on the LLM server. However, this of course means that I will need a more powerful UPS, which I do not have the space for.
My plan is to get a second power supply to power only the GPUs. I do not want to put this PSU on the UPS. I will turn on the second PSU via an Add2PSU.
In the event of a blackout, this means that the base system will get full power and the GPUs will get power via the PCIe slot, but they will lose the power from the dedicated power plug.
Obviously this will slow down or kill the LLM server, but will this have an effect on the rest of the system?
I do something similar to op, however, running llms is what finally convinced me to switch over to kubernetes for these exact reasons, I needed the ability to have gpus running on separate nodes that then I could toggle on or off. Power concerns here are real, the only real solution is to separate your storage and your compute nodes.
What OP is suggesting is not only not going to work, and cause damage probably to the motherboard and gpus, but I would assume is also a pretty large fire hazard. One GPU takes in an insane amount of power, two gpus is not something to sneeze at. It’s worth the investment of getting a very good power supply and not cheaping out on any components.
