Hi All,
Unfortunately I am a noob so YMMV with this.
I could not find any detailed posts that collated all the various breadcrumbs of information required to make this work.
This is my attempt to document it for others. (and for myself)
I am sharing Zpool/datasets via SAMBA to Windows machines and NFS to linux machines.
I am using sanoid to create and manage snapshots on my zpools and syncoid to replicate snapshots to secondary tier storage.
I wanted to natively access the Shadow copies/Previous versions in explorer on my mapped drives in Windows 11.
sanoid use colons as snapshot names and this is a problem for samba export/windows explorer to read exposed Zpool snapshots.
Setup Zpool Datasets, Sanoid etc to your liking and check that you can see the snapshots in: .zfs/snapshot on your OMV machine.
Create your samba shares on zfs/zpools/datasets etc as per normal in OMV GUI -> Services -> SMB/CIFS -> Shares and test that you can access with Windows Explorer.
When verified in Windows Explorer that it is working, go back to your OMV GUI -> Services -> SMB/CIFS -> Shares, and select the Zpool share of which you want to expose the Sanoid Snapshots/Shadow copies.
Edit your Share.
Add the following in the Extra options of the share in the GUI, one item per line:
vfs objects = shadow_copy2, catia
catia:mappings = 0x22:0xa8,0x2a:0xa4,0x2f:0xf8,0x3a:0xf7,0x3c:0xab,0x3e:0xbb,0x3f:0xbf,0x5c:0xff,0x7c:0xa6
shadow: snapdir = .zfs/snapshot
shadow: sort = desc
shadow: format = _%Y-%m-%d_%H:%M:%S
shadow: snapprefix = ^autosnap
shadow: delimiter = _
shadow: localtime = no
Click Save and then Apply.
You should now see Previous Versions and all the Snapshot dates etc in Windows Explorer properties.
TLDR;
sanoid use colons as snapshot names and this is a problem for samba export/windows explorer to read exposed Zpool snapshots
We use catia:mappings to re-map the illegal Window Name Characters (colon) for the samba export otherwise Windows will not display it.
Now we don't have to edit the naming convention in sanoid scripts every time sanoid is updated by a deb package.
Before anybody asks: I do not want to use zfs-auto-snapshot. My own reasons, I prefer sanoid.
Hope this helps.
All credit to those before me that posted the various one liners etc.