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n2d4 • today at 4:52 PM • 1 reply • view on HN

Cool! I've been using your API for running sandboxed JS. Nice to see you also support VMs now.

    > we mean forking the whole memory of it
How does this work? Are you copying the entire snapshot, or is this something fancy like copy-on-write memory? If it's the former, doesn't the fork time depend on the size of the machine?

Replies

benswerd • today at 5:02 PM

We're using copy on write with the memory itself. Fork time is completely decoupled from the size of the machine.

Creating snapshots takes a 2-4 second interruption in the VM due to sheer IO that we didn't want here.

Whats especially cool about this approach is not only is fork time O(1) with respect to machine size, but its also O(1) with respect to the amount of forks.