When I recall correctly, an NFS share on a 325 is a subdirectory in /i-data/md0/nfs/. Deleting a share deletes the subdirectory on disk.
The bad news is that there is no 'undelete' on the NAS. The good news is that the data is not actually wiped from the disk, deletion is only administrative. But the sectors are marked as unused, and can be re-used at any moment. So if you want to recover, switch off the NAS immediately.
There are 2 ways to recover the data. (as far as it's still on the disk). The data volume has an ext3 filesystem. You can try
extundelete to recover the files. For that you need to connect the disk to a Linux computer, assemble the raid array (a single disk volume on a zyxel is also in a raid array) and follow the instructions on the page.
The other way is low-level recovery. A program like
PhotoRec can search the surface of the disk for recognizable files, by looking at known headers, and restore them. In order to do so the file needs an recognizable header, so for instance flat text files can't be found this way, and the files may not be fragmented, as there is no help from the filesystem to connect the fragments.
Fortunately most media files have a good header, and fragmentation on a Linux NAS is low, as long as the disk is not almost full.
As low-level recovery works without help of the filesystem, you don't need an OS which 'knows' the filesystem, so any OS supported by the tool is sufficient.
A big drawback of low-level recovery is that it recovers
files, not the metadata, as the metadata is stored in the filesystem. The metadata here is filename (including subdirectories) and timestamps. Another one is that you might restore corrupted or bogus files, without knowing it.
When you want to use extundelete it's a good practise to create a bit-by-bit copy of the disk first, using dd, or something like that. Any write done to the filesystem can corrupt or erase a file.
