Why We Replaced Firecracker with QEMU | Hocus Blog

At CodeSandbox we use Firecracker for hosting development environments, and I agree with the points. Though I don't think that means you should not use Firecracker for running long-lived workloads.

We reclaim memory with a memory balloon device, for the disk trimming we discard (& compress) the disk, and for i/o speed we use io_uring (which we o... See more

A good mental model is that Qwik applications at any point of their lifecycle can be serialized and moved to a different VM instance (server to browser). There, the application simply resumes where the serialization stopped. No hydration is required. This is why we say that Qwik applications don't hydrate; they resume.