A little old topic but i was just wondering what the command lun share <path> actually does? You can see the LUN as a file wether you share it or not, so what is that for ; regarding that you cannot get access to the lun over NAS and :
Note A LUN cannot be extended or truncated using NFS or CIFS protocols.
If you want to write to a LUN over NAS protocols, you must take the LUN offline or unmap it to prevent overwriting data in the LUN using the SAN protocol. To make a LUN accessible to a host using a NAS protocol, complete the following steps.
Determine whether you want to read, write, or do both to the LUN over the NAS protocol and take the appropriate action:
If you want read access, the LUN can remain online.
If you want write access, ensure that the LUN is offline or unmapped.
I saw a post about someone who used "losetup" on Linux and "lofiadm" on Solaris to do a loopback mount... mount a volume with a shared lun over nfs. Then use the loopback mount to the lun in the nfs mount. It is pretty slick, but I'd wonder why you wouldn't use iSCSI instead to mount the lun directly to get block i/o to the device. Or like Adam mentioned, a way to backup a lun over nfs by mounting the volume.