Hi Mike,
What do you mean by Structured data file?
FSRM use Host Agent to collect Host side usage and statictics like, file size, access time, last user accessed, etc.
This can be done on CIFS shares,Mapped Network Drives(can be both Cifs Shares or LUN),Local Drive(C:/, D:/) etc in case of Windows boxes.
In case of linux and Solaris boxes they work on mount paths, which can even be luns, or nfs exported volumes or qtrees.
Regards
adai