I had a situation with a server misconfig. Nginx was unable to write its logs due to invalid file permissions and checking with free
the buffers/caches were at about 3.2GB (out of 4GB Memory).
Nginx master process was able to write logs - but the child processes could not open the logs. (Nginx error log revealed this)
The system failed because it ran out of disk space (checked syslog). However, just before it failed disk space checked with df
was plentiful.
What's the underlying explanation for this?