Builds 1244-1249 died on mkdir of the run dir with 110GB free and 16% inodes.
Ruled out: actual disk (df sampled every 2s across a failing build never moved),
inodes, quotas, a poisoned parent directory (61/61 stress creations succeeded),
runner sandboxing (namespaces identical to the host), and a wedged runner
(restart changed nothing). The same harness with the same numeric run id, run by
hand outside drone, worked every time.
Recreating the runs directory with a fresh inode preceded recovery; builds have
run normally since. The root cause is NOT established, so the note says so rather
than presenting a fix that might be coincidence.
autonomic-bot
ecf126d98d