VirtioFS Support Page

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6 hours ago, Rodrigo Alves said:

I was able to configure the drive in windows 10, but when I copy a file I get an error saying "the file's properties cannot be copied". Can someone help me please?


Try running the "docker safe new perms" tool under the tools menu in unraid. Good place to start when you run into any permissions issues.

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On 11/27/2022 at 2:00 PM, johnsanc said:

Have there been any updates on the freeze issue several people are having whenever memoryBacking is enabled?

Can you confirm your memorybacking options? I was running with just memfd  and shared, but can you try including nosharepages also if you are not already?


    <source type='memfd'/>
    <access mode='shared'/>


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17 hours ago, TexasUnraid said:


Try running the "docker safe new perms" tool under the tools menu in unraid. Good place to start when you run into any permissions issues.

unfortunately it didn't work..


i'm struggling to get my Gdrive folder on that share, but gdrive doesn't accept mapped drives, figured this would be a great solution for me..

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It looks like this is still very unstable. Steam is unable to download games to the drive. I get disk write and read errors without being able to even start the download. I have checked permissions, run new permissions tool, run steam with admin privileges and so on. Steam logs dont say anything more either. Mounting the same share as a network drive works perfectly fine.


Running windows 11 Pro 22H2. Any further suggestions are welcome.

Edited by m33ts4k0z
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On 11/24/2022 at 6:48 PM, KptnKMan said:

I'm testing Virtiofs on my main Win11 VM, and having quite some success, but with a few caveats.


Firstly, while installing the latest virtio drivers, my VM IMMEDIATELY CRASHES.

I found through lots of trial and crashes that if I leave "Fwcfg" DISABLED, the install finishes.

Disabling it allows install of updated drivers, sets up services, and does not crash the VM.


What is this Fwcfg, can anyone shed some light on that?


Secondly, I'm trying to setup 2 virtiofs disks, but only 1 appears as the Z: drive

If I setup 2 drives, only the second appears as Z: when the VM boots.

In this example, I setup "vdata1" and "vdata2":



Thirdly, the virtiofs is always set as Z:

I cannot find or see any way to reassign the drive letter, or indeed use multiple drive letters.

Is there a way to change the assigned drive?


I have not tested but I have put a link to multi instance doc here 


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  • 3 weeks later...
4 hours ago, mackid1993 said:

So far my Win 11 VM has been up 7 hours and 30 minutes without crashing yet with the newest 229-1 drivers. Hopefully we finally have stability now.

Are you running windows? if so what version of winfsp are you running?

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14 hours ago, SimonF said:

Are you running windows? if so what version of winfsp are you running?

I'm running Windows 11. WinFsp is 2022.2 which was the latest version I could find. With the 229-1 drivers I managed over a day of uptime with no crashing so far. Before it would have completely locked up after about 10-12 hours.

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Discovered Something I thought I would share,


If you find that some EXEs will not run directly from a mounted share in Windows, in particular, EXEs that require Admin Rights to run. Make sure that the Windows Service "WebClient" is Running. If not set it to Automatic and Start it. This was the case for me on a Windows 11 VM. Milage May Vary!


Google-Fu, To The Rescue!
Error 0x800704b3 when launching application from HFS+ volume

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  • 4 weeks later...

I actually just re/built from scratch about 2 hours ago a new win11 guest vm on my unraid host because my last one was locking up and or seizing up all cpu's attached to the guest. I tweaked the heck out of the guest os, so I wasnt sure if it was my tweaking things too much or one or many of the mounted shares via VirtioFS. il share back in a few days or so if mine locks up or not. But if others are having same behavior then I'm not gonna hold my breath!



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Just checking back in! The VM I rebuilt from scratch has been up without issues (idle most of the time) since friday and all is stable with unraid host and the vm. I have 5 different VirtioFS mounts in Windows 11 Pro 22H2 guest vm. I also have memoryBacking enabled as per requirements to get mounts to work in windows. I didnt tweak anything really at all in guest os. im sure that helps as I can get carried away at times in misc windows tweaks.



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  • 1 month later...

VirtioFS and Memory backing seems much more stable in 6.12-rc2. I have almost a day of uptime and I'm backing up to backblaze in my Windows VM with no issue.


I found this ( article to help mount multiple shares with VirtioFS with different drive letters. I have task scheduler run a batch script with elevated permissions at boot.


You can set each individual share as a Mount Point in the VM manager like this:



First step to do this you first have to stop and disable the VirtioFS Service:

sc stop VirtioFsSvc
sc config VirtioFsSvc start=demand


Then run the command while putting in the location of your VirtioFS.exe


"C:\Program Files (x86)\WinFsp\bin\fsreg.bat" virtiofs "<path to the binary>\virtiofs.exe" "-t %1 -m %2"

 This command makes the necessary changes to the registry.


Then you can mount your different mount points as set in the VM manager with this command:


"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" start virtiofs viofsY mount_tag0 Y:



My completed batch file that I run as admin with task scheduler looks like this:


"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" start virtiofs viofsJ Archives J:
"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" start virtiofs viofsl Downloads l:
"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" start virtiofs viofsM Music m:
"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" start virtiofs viofsS Software s:
"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" start virtiofs viofsT TV T:
"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" start virtiofs viofsU Movies U:
"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" start virtiofs viofsV Backup V:
"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" start virtiofs viofsY CommunityApplicationsAppdataBackup Y:



To unmount drives you run this command:


"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" stop virtiofs viofsY


My unmount script looks like this:


"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" stop virtiofs viofsJ
"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" stop virtiofs viofsl
"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" stop virtiofs viofsM
"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" stop virtiofs viofsS
"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" stop virtiofs viofsT
"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" stop virtiofs viofsU
"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" stop virtiofs viofsV
"C:\Program Files (x86)\WinFsp\bin\launchctl-x64.exe" stop virtiofs viofsY


So far this works great with backblaze personal backup under Windows. I have 22 hours of uptime backing up with no lockups yet. I found it helpful to limit the number of threads backblaze uses to 8 which is the recommended and to also give my VM 16 GB of RAM.

Edited by mackid1993
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Just another update, it seems like 16GB of RAM is a must for Backblaze at least with the amount of data I have. I now decided try balooning the RAM so I set the min to 4096 MB and the max to 16384 MB. Now to wait 24 hours again and see if it locks up on me. So far Task Manger is confused but things are stable and there is much more memory for unRAID itself.

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