InnoDB Corruption

InnoDB stores its data and indexes in shared tablespaces. If the server was started with the option --innodb_file_per_table at the moment of table creation, it also has its own datafile, but the table definition still exists in a shared tablespace. Understanding how table files are stored can help to effectively maintain the data directory and backups.

InnoDB is a transactional storage engine and has internal mechanisms that automatically fix most kinds of corruption. It does this recovery at server startup. The following excerpt from the error log, taken after a backup by MySQL Enterprise Backup (MEB) using the mysqlbackup --copy-back command, shows a typical recovery^[6]: