The folder /backup is the root of the disk. I mounted the disk there, doing the ls -l /backup showed all the root folders on the disk. Perhaps there is something going on with the PC folders, as the lost+found and trash folders are both empty.
I'm not sure how I can go about determining if a particular backup is using the pool or just storing the files in the PC folder. What's the best way to check if a given backup set is represented in the pool or not? Would knowing the size of all the pc folders help narrow it down?
I'm not sure if this is the best way to check the hard linking, but here's a test I thought might be helpful. I did this command to see if a common file in these backups are pointing to the same inodes.
bash-4.1$ ls -i /backup/pc/*/*/ffileshare/fWindows/fexplorer.exe
The output is long so I'll give a snippet:
bash-4.1$ ls -i /backup/pc/*/*/ffileshare/fWindows/fexplorer.exe
635979167 /backup/pc/120p1m1/75/ffileshare/fWindows/fexplorer.exe 646452561 /backup/pc/7qk56d1/79/ffileshare/fWindows/fexplorer.exe
635979167 /backup/pc/120p1m1/76/ffileshare/fWindows/fexplorer.exe 646452561 /backup/pc/7qk56d1/80/ffileshare/fWindows/fexplorer.exe
635979167 /backup/pc/327kkn1/87/ffileshare/fWindows/fexplorer.exe 646452561 /backup/pc/7qk56d1/81/ffileshare/fWindows/fexplorer.exe
635979167 /backup/pc/327kkn1/88/ffileshare/fWindows/fexplorer.exe 646452561 /backup/pc/7qk56d1/82/ffileshare/fWindows/fexplorer.exe
And it continued like that which shows me that a common file is going to the same inodes in these backups which tells me the pool should be working in theory. (I'm assuming the 2 variants account for different versions of windows.)
So I'm pretty stumped at how to figure out what happened to it.