Can open files be unlinked on NFS mounted volumes while applications that still have them open read/write?

Solution 1:

The short answer is yes with caveats.

Since NFSv3 is stateless, the NFS client driver accomplishes this with something called "silly rename", where the deleted file is renamed to something like .nfsXXXXXXXXXX. This generally works, but there are a few caveats compared to a local filesystem. For instance, if the client crashes then those .nfsXXXX files will not be deleted, and you'll have to clean them up manually.

I think as of NFSv4.1 the protocol has the required features to implement delete-on-last-close without silly rename, but I don't know if any clients/server yet implement this.