zlacker

>>hugodu+(OP)
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 only use for scratch disks, the project disks are network disks).

It's a tradeoff. It's more work and does require custom implementations. For us that made sense, because in return we get a lightweight VMM that we can more easily extend with functionality like memory snapshotting and live VM cloning [1][2].

[1]: https://codesandbox.io/blog/how-we-clone-a-running-vm-in-2-s...

[2]: https://codesandbox.io/blog/cloning-microvms-using-userfault...

>>CompuI+IL
These blogs are wonderful. I'd read them before figuring out firecracker snapshot/restore, but wanted to say it here.

> i/o speed we use io_uring

custom io_uring based driver for the VM block devices? or what do you mean here?