Usually expanding LUN would be done on the NetApp, then the filesystem expanded by the host.
This allows the NetApp to optimize the storage (even to copying the blocks if necessary) without affecting the data.
Now doing something like changing the stripe width on the NetApp would be a different thing. I don't know if the current NetApp OS knows how to copy a lun and still get the block addressing right. I believe it would have to copy the lun to a new one for that to work. Adding to a lun (without changing the striping) should be easy - just append the extension to the end of the existing LUN. I believe the documentation for the NetApp would have the instructions (though the specific instructions might be hard to find - I found their documentation fairly complete, but with some things scattered).
One problem with expanding the filesystem is that some things don't necessarily get expanded (inode table I think, but not sure). If the filesystem is xfs, no problem as the inode list is already dynamically expandable (which is why you may see huge inode numbers - I think they are also the block number of the inode).
NOTE: It has been over 5 years since I worked with NetApp storage devices.
As always, be sure you have something for a backup. Sometimes it is easier and safer to create a new bigger lun, create the new filesystem, and copy the old filesystem. The old lun is the backup...
Last edited by jpollard; 05-11-2016 at 09:37 PM.