Incomplete installtion of WLS. What now?

I tried installing WSL on a Win10 21H1 system but the installation failed. I need some suggestions for my next step.

Several tutorials on the web for installing WSL don't mention the Hyper-V Virtualization requirement, and I blindly followed one of them. (For instance, the Prerequisites section of the Microsoft article https://docs.microsoft.com/en-us/windows/wsl/install doesn't mention virtualization.) I started the installation on a computer without Hyper-V Virtualization enabled. A lot of activity took place before the installation failed. Programs and Features shows I have WSL installed but I know the installation of Ubuntu failed.

If I decide to switch to a different computer, what do I have to do to clean up the incomplete installation? Do I just uninstall WSL or are there other things that need to be removed or changed?

If I decide to enable Hyper-V Virtualization on this computer, how do I pick up the installation? Uninstall WSL and start over from the top? Or is there some way to tell where I failed and pick up from there? (I can't guarantee that it was just the Ubuntu installation that died.)

Thanks. I uninstalled WLS and will try it on a different PC.

I have had no experience with VMs since working with IBM's VM/370 in the mid 1970s. Is there a downside to activating Hyper-V - a performance hit or something? Windows natively handle all it's I/O, or is that turned over to a hypervisor?

Hi there
The trick in using VM's is to minimise as much as possible overhead by the host operating system, disk I/O and graphics.

Graphics can be passed thru natively to a VM if you have 2 graphics cards or 2 separate graphics ports, although this is much more important for gamers. I/O is the real killer (assuming there's enough RAM as well in the system). If you can use "Native I/O" for the Guest's file systems you can save very considerable Disk I/O slowdown -- for example if using a Linux VM on a Windows host setting the initial virtual Disk (the one the Guest boots from) to a "Physical disk to type NVME (if you have VMWare workstation) and attaching a "physical Disk" you can then use extremely an efficient file system on a Linux VM (f2fs) which was specifically designed for the latest ssd's and nvme type of ssd's. You can also attach linux formatted USB drives which you can share across your network (at least you can if you enable "Bridged Networking" in the VM which makes the VM a good NAS server.

Using a vhdx physical disk for the Windows Host also makes sense as the Windows system that boots these is actually a tiny graphical VM -- which gives you a graphical boot menu and is running a very efficient "internal FS".

I've found running Windows and other VM's from a Windows Host which itself is on a physical vhdx file and attaching another vhdx file for the VM as a physical disk really improves the performance of the VM considerably.

I'd try a lot more with HYPER-V which essentially runs the whole kernel when enabled so Windows overhead on VM's running under HYPER-V is very good if it wasn't a real hassle of trying to get the wretched thing to run easily in Bridged mode so access to the VM from OUTSIDE the HOST wasn't such a hassle and plug and play to USB devices could be better via a proper usb-arbitration service.

The main drawback in VM's of course is the "paravirtualised" hardware -- however for a lot of people that makes VM's really useful as they aren't too dependent on the actual hardware of the HOST system. It's always a trade off but VM's have become very much better over the last few years (apart from more powerful hardware availibilty).

Cheers
jimbo

pokeefe0001 said:

Thanks. I uninstalled WLS and will try it on a different PC.

I have had no experience with VMs since working with IBM's VM/370 in the mid 1970s. Is there a downside to activating Hyper-V - a performance hit or something? Windows natively handle all it's I/O, or is that turned over to a hypervisor?

WSL doesn't require Hyper-V itself. It does require some components of Hyper-V. The downside of Hyper-V is that it's only available and fully supported on Windows 10 Pro or Windows 11 Pro. The home versions don't support it.

Another downside is that if you have Hyper-V installed, and later decide to use VMWare or VirtualBox, the performance of running VM's on those platform will be pretty poor unless you create a boot entry such that you can boot into Windows 10 without HyperV enabled.

I decided not to activate virtualization on my "production" PC. Instead, I activated it and installed WSL on an old "test" PC that usually does little beyond running backups. No worries about hits to performance there.

My only reason for installing WSL is to test use of an rsync daemon on a NAS. (I had tried using cwRsync on Windows but ran into so problems so wanted to try real rsync client.) Once I've done that testing I'll probably uninstall WSL and disable virtualization.

But I've got a question about disabling virtualization. I can easily turn off the Hyper-v feature in Windows. Do I also need to turn off virtualization in BIOS?