I am wondering if there really might not have been a DOS attack going on. First time in 5 years, but there's a first time for everything I guess. Just to say that normally when I do a top I see a load of like .10 to .20 unless I am doing something strenuous like doing an entire backup of the server, in which case it can to up to past .50 or .60. Nothing more. And each week I reboot when I see available RAM starting to drop a bit.
I will definitely install ClamAV as soon as the current "flight" is over and the plane is in the hangar as it were and see what's going on here. Again, things have been going just fine over the past couple years, so I was a little surprised to see this. Thank goodness a physical button-press reboot in the room with the machines whirring away by the conscientious team at the place I have my server sitting fixed this. (While previous attempts to do software reboot via their remote interface didn't. At which point I began to ready one of my business-continuity parachutes.) For the past 48 hours all is well.