Ksm

Every homelab eventually runs into the same wall: you’ve got more VMs you want to run than RAM to dedicate to them if each one reserves its full allocation up front. Proxmox gives you two tools that let you push past that wall, memory ballooning and KSM, and both get treated by a lot of guides as a free lunch you just flip on. They’re not. They buy you real headroom, but only if you understand what each one is actually doing underneath, because the failure mode when you push either one too far isn’t a warning, it’s an OOM kill or a host that grinds to a crawl. ...