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Accessing the Windows filesystem from WSL and vice versa is extremely slow, so running for example your IDE in WSL and having your code etc. stored in WSL is us

Accessing the Windows filesystem from WSL and vice versa is extremely slow, so running for example your IDE in WSL and having your code etc. stored in WSL is useful. I think that is one of the big usecases. It's already kinda supported in vscode, where it runs a vscode server in WSL and Windows just runs the frontend. It's useful for me when developing dotnet intended for Linux as I can store the code in WSL and be able to build, debug, run docker and so on directly from vscode.

hasperdi 5y ago
Are you talking about WSL1 or WSL? Wsl2 is much much faster due to having a virtualized real linux kernel running
- scandinavian 5y ago
  Accessing the WSL filesystem from WSL is indeed a lot faster on WSL2. Accessing the Windows filesystem from WSL or vise versa is even slower in WSL2 compared to WSL1. https://docs.microsoft.com/en-us/windows/wsl/compare-versions#comparing-features https://docs.microsoft.com/en-us/windows/wsl/compare-version... > As you can tell from the comparison table above, the WSL 2 architecture outperforms WSL 1 in several ways, with the exception of performance across OS file systems.
- easton 5y ago
  System performance is, IO between Windows and Linux isn’t. https://github.com/microsoft/WSL/issues/4197 https://github.com/microsoft/WSL/issues/4197
- speed_spread 5y ago
  WSL2 disk access from the Windows side is very slow. It's the reciprocal problem of WSL1. WSL2 Linux apps now get proper performance now but if your IDE is on the Windows side, access time to project files on native Linux partition is terrible.
  - LaGrange 5y ago
    ...actually e.g. VS Code has a really great split backend, so you can actually have the frontend "properly" on Windows anyway, and yet still use WSL2. My own case was something different: annoyingly configured automated browser tests with Cypress. Just running them inside WSL and letting that start a browser on the distro itself was the most comfortable way to debug these.
r-w 5y ago
But I mean come on, they're Microsoft. If they really wanted filesystem access to be efficient across systems, we'd have it by now. Although convenient, I doubt that's on their list of primary motivations for doing this.
- scandinavian 5y ago
  >But I mean come on, they're Microsoft. If they really wanted filesystem access to be efficient across systems, we'd have it by now. Here's one of the developers saying it is hard back in the WSL days. https://github.com/Microsoft/WSL/issues/873#issuecomment-391810696 https://github.com/Microsoft/WSL/issues/873#issuecomment-391... The reason makes sense to me, but I'm not an expert. Maybe you could expand on why you think they could do it but chose not to?
  - MikusR 5y ago
    Seeing how every file system (NTFS) imrovement since windows 7 (like new compression methods) is done in layers running on top of ntfs. I think that Microsoft has either lost the source to ntfs driver or institutional knowledge of how it works.
    - jdub 5y ago
      The real answer is that they're building filters on top of NTFS because that's precisely how it was designed to work.
      - CRConrad 5y ago
        GP's explanation was almost as plausible, and much funnier.
ineedasername 5y ago
Why is it so slow? I use VMware player and swapping files is fine. WSL2 seems like it's just using a lightweight VM over HyperV... is Hyper V really that much worse than VMware (and VBox) in this?
- sterlind 5y ago
  WSL2 uses 9P (of the venerable Plan 9 pedigree, I assume because Erick Smith is a nerd!) to remote the filesystems. I don't think that's part of HyperV (though it could be a custom VSP/VSC, and that channel is ridiculously slow.) Personally I haven't run into slowness other than Windows sucking at copying lots of small files, which is NT's fault for allowing FS filter drivers and their ridiculous locking scheme.

hasperdi 5y ago

Are you talking about WSL1 or WSL? Wsl2 is much much faster due to having a virtualized real linux kernel running

scandinavian 5y ago
Accessing the WSL filesystem from WSL is indeed a lot faster on WSL2. Accessing the Windows filesystem from WSL or vise versa is even slower in WSL2 compared to WSL1. https://docs.microsoft.com/en-us/windows/wsl/compare-versions#comparing-features https://docs.microsoft.com/en-us/windows/wsl/compare-version... > As you can tell from the comparison table above, the WSL 2 architecture outperforms WSL 1 in several ways, with the exception of performance across OS file systems.
easton 5y ago
System performance is, IO between Windows and Linux isn’t. https://github.com/microsoft/WSL/issues/4197 https://github.com/microsoft/WSL/issues/4197
speed_spread 5y ago
WSL2 disk access from the Windows side is very slow. It's the reciprocal problem of WSL1. WSL2 Linux apps now get proper performance now but if your IDE is on the Windows side, access time to project files on native Linux partition is terrible.
- LaGrange 5y ago
  ...actually e.g. VS Code has a really great split backend, so you can actually have the frontend "properly" on Windows anyway, and yet still use WSL2. My own case was something different: annoyingly configured automated browser tests with Cypress. Just running them inside WSL and letting that start a browser on the distro itself was the most comfortable way to debug these.

r-w 5y ago

But I mean come on, they're Microsoft. If they really wanted filesystem access to be efficient across systems, we'd have it by now. Although convenient, I doubt that's on their list of primary motivations for doing this.

scandinavian 5y ago
>But I mean come on, they're Microsoft. If they really wanted filesystem access to be efficient across systems, we'd have it by now. Here's one of the developers saying it is hard back in the WSL days. https://github.com/Microsoft/WSL/issues/873#issuecomment-391810696 https://github.com/Microsoft/WSL/issues/873#issuecomment-391... The reason makes sense to me, but I'm not an expert. Maybe you could expand on why you think they could do it but chose not to?
- MikusR 5y ago
  Seeing how every file system (NTFS) imrovement since windows 7 (like new compression methods) is done in layers running on top of ntfs. I think that Microsoft has either lost the source to ntfs driver or institutional knowledge of how it works.
  - jdub 5y ago
    The real answer is that they're building filters on top of NTFS because that's precisely how it was designed to work.
    - CRConrad 5y ago
      GP's explanation was almost as plausible, and much funnier.

ineedasername 5y ago

Why is it so slow? I use VMware player and swapping files is fine. WSL2 seems like it's just using a lightweight VM over HyperV... is Hyper V really that much worse than VMware (and VBox) in this?

sterlind 5y ago
WSL2 uses 9P (of the venerable Plan 9 pedigree, I assume because Erick Smith is a nerd!) to remote the filesystems. I don't think that's part of HyperV (though it could be a custom VSP/VSC, and that channel is ridiculously slow.) Personally I haven't run into slowness other than Windows sucking at copying lots of small files, which is NT's fault for allowing FS filter drivers and their ridiculous locking scheme.