Come to find out that Ubuntu 11.10 uses NFS V4 by default, which means the various clients scattered around here, all of which use NFS V3 by default, report all files have user & group 232 – 2: an awkward and unforgettable unsigned 4294967294. That’s -2 in 2’s complement notation with 32 bit hex numbers, corresponding to the unsigned 16-bit 65534 = -2 for the nobody user & group.
Fix that by editing /etc/default/nfs-common to set NEED_IDMAPD=yes. Unmount the NFS share, do sudo start idmapd, remount, and it’s all good. The next time the client boots, the idmapd daemon starts automagically, and that’s all good, too.
Adding the -t nfs4 filetype in /etc/fstab seems to be not necssary.
How I got into this mess: the Intel Atom D525 that had been driving the Thing-O-Matic has a bog-standard Intel graphics chip that, despite (or perhaps because of) having an open-source video driver, reports doing only OpenGL 1.4. OpenSCAD, however, requires OpenGL 2.0 and those hacks don’t allow it to run properly, which makes it awkward for demos. The AMD that’s currently the file server has, IIRC, better graphics that might improve the situation; I think it sports a somewhat peppier processor, too. The fact that it’s running Ubuntu 8.10 says that it’s time for an update.
Soooo, I swapped in a new 1.5 TB SATA drive, installed hot-from-the-oven Ubuntu 11.10, replaced Unity with XFCE, inhaled all the current data from the file server’s external USB backup drive, configured ssh / nfs / etc, and I’m now doing some simpleminded tests before I swap the IP addresses.
Now, if the AMD has craptastic graphics hardware, it’s unhappy dance time…