This is the place to post your virtfs (9p) configuration and speed tests.  Let me know if we need any additional questions added.

 

Post one of your XML passthrough sections:

 

    <filesystem type='mount' accessmode='passthrough'>

      <source dir='/mnt/user/Movies'/>

      <target dir='movies'/>

    </filesystem>

 

Post your guest fstab line:

 

movies /storage/movies  9p trans=virtio,version=9p2000.L,nobootwait,rw,_netdev    0   0

 

1.  Source location (array disk / cache disk / non-array partition)?

2.  What type of source device was used (ssd or hdd)?

3.  Was the source referenced in your XML a user share (/mnt/user) or directly to a disk device (/mnt/disk1 or /mnt/cache)?

4.  Same questions for the target location / device.

5.  And for the target device, if referenced in your XML using a user share, was that user share cache enabled?

6.  What is the filesystem of your VM store (BTRFS, XFS, RFS, etc.)?

7.  What command/tool was used to test speed (if DD, post the full command)?

8.  What average speed are you seeing (MB/s)?

 

Here is mine...

 

    <filesystem type='mount' accessmode='passthrough'>

      <source dir='/mnt/user/Movies'/>

      <target dir='movies'/>

    </filesystem>

 

Post your guest fstab line:

 

movies /storage/movies  9p trans=virtio,version=9p2000.L,nobootwait,rw,_netdev    0   0

 

1.  array disk

2.  hdd

3.  /mnt/user

4.  hdd  /mnt/cache (qcow2)

5.  N/A

6.  BTRFS

7.  MC

8.  ~15.MB/s

<filesystem type='mount' accessmode='passthrough'>
      <source dir='/mnt/user/Recordings'/>
      <target dir='recordings'/>
      <address type='pci' domain='0x0000' bus='0x02' slot='0x05' function='0x0'/>
    </filesystem>

 

recordings /mnt/recordings  9p trans=virtio,version=9p2000.L,nobootwait,rw,_netdev    0   0

 

1. Array disk

2. HDD

3. /mnt/user

4. SSD /mnt/cache (Qcow2 and Raw tested)

5. NA

6. BTRFS (Not sure if you mean the cache disk or the file system inside the VM. Ext4 filesystem inside VM)

7. Rsync

8. 75MB/s

 

Updated some info as it seems you changed the questions in the first post.

I've just setup and tested this today, I'm not impressed with the speed. My setup is nearly identical to yours johnodon so maybe there's something in that. I'm testing this using XBMCbuntu, I have a second VM Windows 7 that lives on the same cache drive and copying the same file via SMB gave me 50MB/s still not great but double 9p. 

 

    <filesystem type='mount' accessmode='passthrough'>
      <source dir='/mnt/user/Media'/>
      <target dir='media'/>
      <address type='pci' domain='0x0000' bus='0x02' slot='0x05' function='0x0'/>
    </filesystem>

 

media /mnt/media  9p trans=virtio,version=9p2000.L,nobootwait,rw,_netdev    0   0

 

 

1.  array disk

2.  hdd

3.  /mnt/user

4.  hdd  /mnt/cache (qcow2)

5.  N/A

6.  BTRFS

7.  RSync

8.  25.MB/s

    <filesystem type='mount' accessmode='passthrough'>
      <source dir='/mnt'/>
      <target dir='shares'/>
      <address type='pci' domain='0x0000' bus='0x02' slot='0x05' function='0x0'/>
    </filesystem>

 

shares /mnt  9p trans=virtio,version=9p2000.L,nobootwait,rw,_netdev    0   0

 

1.  array disk

2.  hdd

3.  /mnt

4.  ssd  non-array disk  /mnt/apps/VM/images (qcow2)

5.  no cache

6.  xfs

7.  mc

8.  60 MB/s