also interested in the upper limit of a micro vm, like how big can it get? 64gb memory? not really micro any more and maybe a traditional VM would be a better fit.
Unrelated TIL: AWS Fargate has supported Windows since last October. I work at AWS and “specialize” in serverless and I didn’t know that.
On the other hand, CodeBuild has supported Windows containers for years and at least CodeBuild for Linux is based on Fargate, so the service team figured something out. (I had to figure out how to word that. I can’t say “they figured it out” since I work for the same company. But I couldn’t say “we” since I’m so far removed from any service team in the consulting department that it would be disingenuous)
Another (unrelated) test we've done is on overprovisioning memory. We were able to run 200 VMs (all running Vite dev server where a file was changed every second) with 2GB RAM per VM, on a node with 128GB RAM. Because we were mapping the memory files on disk directly to the VM, the VM would automatically "swap" the memory back to the memory file when it had memory pressure. The bottleneck here was CPU.
The microVM emulates the minimal possible set of devices needed to run, such as disks and network devices, and in the specific case of firecracker, through the use of the virtio model. So it can theoretically use huge amounts of memory of a large vCPU count and still be a microvm.