What is `innodb_log_file_size` and how does it affect MySQL shutdowns?

`innodb_log_file_size` controls the size of the InnoDB redo log files. If these files become too large, MySQL may experience performance issues and can shut down unexpectedly. Increasing `innodb_log_file_size` can improve write performance, but it's crucial to monitor its impact on performance. A smaller log file size generally leads to more frequent log file flushes.