When couchdb cannot write to its log file erlang just crashes without any hint what is going wrong. This happens for instance if the log file directory path does not exists.
In some older releases (0.9) it seemed to have created the missing directories automatically (if permissions are ok). 0.10 does not even try to create the directories. The log path needs to exist.
At least a proper error message should be added to make clear that there is a problem writing the log file.