[pve-devel] [PATCH cluster/guest-common/docs/qemu-server/manager v15 0/12] virtiofs

[Markus Frank]

On  2025-04-04 10:27, Lukas Wagner wrote:
> On  2025-04-03 12:34, Markus Frank wrote:
>> Virtio-fs is a shared file system that enables sharing a directory
>> between host and guest VMs. It takes advantage of the locality of
>> virtual machines and the hypervisor to get a higher throughput than
>> the 9p remote file system protocol.
>>
> 
> Some thoughts - no blockers though, can easily be done in follow-ups:
> 
> - Thinking through my potential use-cases for a feature like this, I think it would be pretty nice
>    to expose the 'readonly' flag [1] under 'Advanced', the same way you did it with e.g. "Allow Direct IO"
readonly does not exist in virtiofsd 1.10.1. Could be a feature for PVE 9.0.
> 
> - I'd remove the "Make sure the directory exists." banner in the "Add Dir Mapping" dialog.
>    People get an error message any way when they try to create a mapping and the directory
>    does not exist.
I would keep it, as we currently cannot check if it exists on a different node.
> 
> - I tried this feature out without reading any documentation first, basically to check for any obvious
>    UX issues that are not as clearly noticable if you know how everything works.
>    Trying to add a filesystem passthrough, my first instinct was to go to the VM's Hardware
>    settings. I was presented with a new "Virtiofs" option under "Add".
>    Maybe this could be called "Directory Passthrough" or "Filesystem Passthrough" to better
>    convey what it does? Users might not be aware what "Virtiofs" is if they haven't read the docs.
I think you should read the docs when using Virtiofs because of the current limitations.
Directory Passthrough may sound like it would just work out of the box like bind mounts.
Also there might be different "Directory Passthrough" technologies in the future.
> 
>    Inside the new "Add" dialog I was then stuck at first. It allowed me to select a Directory ID,
>    but I haven't created one yet. As a user it was not completely clear what the next step would be
>    at this point.
>    Maybe this could show a small hint about where to create
>    new mappings? e.g. "Directory Mappings can be managed under Datacenter → Resource Mapping" or alike.
Good idea. I will have it in v16.
> 
> - In the documentation it is not really mentioned that one is able to create a
>    mapping from the GUI. The text reads like you have to use the `pvesh` command to create it.
It is described in the Resource Mapping section that is linked.
> 
> - Maybe some table for the available options (e.g. direct io, cache, etc.) with the effects
>    and possible values would be easier to comprehend than embedding it into free-flowing text.
> 
> As I said, no blockers from my side though :) Great work!
> 
> [1] https://gitlab.com/virtio-fs/virtiofsd#faq
>