The Boxee Box keeps it's index stored locally (AFAIK), so it wouldn't need r/w access. That's why i indeed use r/w permissions via CIFS (to put the files in the directories), and r/o permissions via NFS for the same files (to play them)...like you said, to avoid incompatible filelocking issues.
But, the weird thing is, when using r/o NFS access, -most- movies play ok, and -some- won't (and also won't show up on Boxee's dashboard, once indexing is finished)...although all files have the same permissions, etc.
There may be something with the way those files are read. Perhaps they haven't been indexed before with a writable folder. There's almost certainly something in common with those movies that won't. Figuring that out might not be easy. It may not be the files themselves either but simply the way they have been indexed in the past.
Maybe i'm just focussing on NFS access too much, i want to use it because of it's lower overhead, but as my Boxee is connected to the FreeNAS box via 100Mbit ethernet connection, CIFS performance is probably just fine and stutter-free, even for high-quality HD movies.
AFAIK the lower overhead you are hoping to achieve is mostly with CPU resources and not network resources. Samba(CIFS) is single threaded while NFS is multi-threaded. CIFS used to be VERY chatty, but with v2.0(released with Windows Vista) a lot of the chattiness is gone. Comparing speeds of CIFS versus NFS with my Gb LAN I have been able to be within 1MB/sec of each other, so I don't know why you'd be worried about 100Mbit/sec ethernet and saving a little overhead(if there is even any savings). I consider the protocols themselves to be roughly on par with each other and the implementation(and support on the desktop side) to be the more decisive factors. Since I can saturate 2xGb LAN ports simultaneously with my hardware with CIFS I don't know how NFS would provide any benefit at all that would make me consider going dual-protocol or even switching to NFS. If I had 10Gb/sec LAN hardware then things might be different though(but I'd have to test that before I'd actually consider making a switch).
BTW, in general: simultaneous NFS and CIFS sharing of the same files works ok, if you respects the filelocking issue :)
Don't fool yourself and think that YOU can respect the file locking issues. Windows XP(and even more so Vista, and even more than Vista with 7 and 8) does a lot(and I mean a whole lot) of stuff in the background. Opening folders that contain sound files, picture files, media files, Office documents(if Office 2007 or newer is installed) and PDFs(if Adobe Acrobat is installed) and probably alot more stuff will trigger alot of things to start happening in the background. For example, caching stuff for text searching, thumbnails, sound file information and tags, video file tags etc. all do things in the background that you sometimes don't even know are happening. While you could disable the ones you can clearly identify are happening(such as thumbnail generation) there are so many that go in that you won't notice I would never ever make the assumption that you are capable of respecting the file locking issues yourself. The consequences could be disastrous for your data too.
I can't find the link, but someone had some application that could fix certain picture corruption issues. He accidentally opened the folder on 2 machines at the same time and this app started "fixing" the pictures that had a bad date in the header of the pictures(year was 1970 or something). Instead, as the explorer addon crawled through his entire picture collection the 2 computers competed with each other and he ended up losing tons of personal pictures of which he had no backup. In fact, he had no clue what had gone on until after the damage was done and he put the puzzle pieces together.
So, for the reasons I've explained(and the example above) I do not tell people to "be careful and respect the file locking issue" as you aren't capable of controlling what your OS does behind your back and you'll become another example of why "you shouldn't do that".
There's lots of things people can do that can be completely harmless and appear to work just fine.. until it doesn't. And when it doesn't you are left with corrupted files(or no files at all). And statistically based on most forum users it seems more than 75% of the time you(the user) won't have good solid up-to-date backups and you'll be losing some of your data forever. Just a few other examples of things that may work until they don't are:
-Using ESXi with RDM.
-Using USB disks as external drives with FreeNAS.
-Using NTFS with FreeBSD for more than simply moving your data to FreeNAS.
Just don't do it if you value your data.
