Hello,
for my problem i tested mhddfs and aufs.
At the end with mhddfs everythings works but aufs has some problems.
My case:
i have 3 disks with no Raid as the disks only contains movies, for that i dont need a secure backup (for private movies i would do that 
)
i want to seperatly access those disks via smb but like to have all the movies together in one folder via smb.
I tryed that befor with gentoo and unionfs witch works great.
Now with omv i did the following:
1. System->Plugins INSTALL "OMV-extras plugin" (google for it)
2. System->Plugins INSTALL "unionsfilesystem 1.7"
3. Storage->FileSystems CREATE filesystem for all disks (daten22 daten23 daten24)
4. Storage->Aufs/Mhddfs ADD with type mhddfs and select all devices (daten22 daten23 daten24)
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5. Access Rights Management->User ADD user / Priviliges read/write for that all filesystems (daten22 daten23 daten24)
6. Access Rights Management->Shared Folders ADD all filesystems (daten22 daten23 daten24) AND "Aufs/Mhddfs" created in step 4. (IMPORTANT I decided to use / for path and NOT the default label=path whyever that is default)
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7. Services->SMB/CIFS->Settings Enable
8. Services->SMB/CIFS->Shares ADD all shared folders from step 6
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You can do the same procedure with aufs it works the same
Now you can connect to your OMV and mount all drives seperate (example \\127.0.0.1\daten22 or \\127.0.0.1\daten23 ...) or all together (example \\127.0.0.1\mergedmhddfs)
I did mount all of them and tryed to create folders and files in all those mounts and see if you can see them merged in the \\127.0.0.1\mergedmhddfs folder.
When you use mhddfs OR aufs you see INSTANTLY all of your created folders and files in the correlate mount point.
For example when you create an folder like \\127.0.0.1\daten22\blurayimage\aliens you can see that folder in \\127.0.0.1\mergedmhddfs and vise versa.
But when you create another folder like \\127.0.0.1\daten23\blurayimage\matrix (USE DATEN23 NOT 22) you can see that folder only with mhddfs automaticaly in the folder \\127.0.0.1\mergedmhddfs\blurayimage.
When you use aufs you need to restart OMV then it works too (but obviously thats no option)
I know that this is NOT the way it should be used and it works automatically when you only use \\127.0.0.1\mergedmhddfs but i want to decide by myself where to put the files !!!!
So thats the reason why i use mhddfs
perhaps this helps somebody
best regards and good luck
lantoeter
