Ceph » rbd

Investigating other things entirely, I had set log max err = 1 in [global]; I started
observing occasional hangs, and could not explain; instrumenting a loop of
while true; rbd rm <nonexistent>; done
I noticed the hang after rbd finished the
last statement of the Rados destructor, which is the last thing I could think to instrument.
gdb got garbage and uninterpretable stacks. I found the log setting by accident.

I suspect some kind of memory corruption with the Log destructor racing against log
calls, but that's only based on a half-analysis of the problem, not any actual evidence.