Mailing the story:

Don’t let the title scare you. This is only on my main file server, which holds both shared material (source tarballs and update packages) and 116G of movie files. It has recently begun to mis-behave under Linux. The specific symptom is a network freeze under heavy I/O load. This is not unknown with the Realtek 8139 Ethernet chipset, but it’s a big hassle when a movie player stops hard because NFS has suddenly disappeared.