wsl2 takes very much longer time to start than wsl1.

[shpirt]

Environment

Windows build number: Microsoft Windows [Version 10.0.19042.804]
Your Distribution version: Debian GNU/Linux 10
Whether the issue is on WSL 2 and/or WSL 1:  WSL2

Steps to reproduce

1. Run wsl --shutdown to terminates all running distributions and the WSL 2 lightweight utility virtual machine.
2. Reopen debian in windows terminal. (or other terminal, it does not matter)

WSL logs:

Expected behavior

The shell starts as quick as the wsl1 does, which only takes less one second.

Actual behavior

It takes 5~6 seconds to start the first shell, with it has opened, open another shell of the same distro did not occupy such long time anymore.
I try to convert it back to wsl1, it just works fine.
And I have try to reinstall the wsl distro, start it in a fresh, this issue still appear.
I do not know this is a bug or not, the search engine does not help, hope someone can help me figure out where the problem is, thanks!

[Biswa96]

It takes 5~6 seconds to start the first shell

WSL2 need to start a VM, no matter how small it is.

open another shell of the same distro did not occupy such long time

Because the VM is already spun up, next Linux kernel handles the later.

start it in a fresh, this issue still appear

This is by-design, not an issue.