I find that my slave disk is full, but I don't understand what makes it full. Can anyone help me explain what this file is? And how it is formed, so that it makes lots of files that make storage full. Check in mysql error log I did not find anything
#sql files are temp tables generated by
ALTER and other maintenance commands. You will need to find what that command is. At that point, you will probably find that it is in a tight loop, either spawning off process after process, or crashing and restarting.
Other clues: The table name (for many of them) includes "ib916". The table is about 7GB in size (disk footprint).