How do I identify InnoDB corruption?

There are a few ways in which we can identify InnoDB Issues. And while the term can be vague, "corruption" is generally used to cover many of them. The best idea is to narrow down the presented error and identify precisely what you're dealing with.

Please note that cPanel, LLC only supports the cPanel-provided software and does not provide general system-administration services. You may, therefore, wish to seek assistance from a qualified system administrator for this issue.

In these circumstances, you will first want to find a reference to corruption in your MySQL Error Log. The MySQL log files are here: 

/var/lib/mysql/HOSTNAME.err

/var/log/mysqld.log

Primarily what you find in the log file will be instances of the following:

mysql: InnoDB: Database page corruption on disk or a failed

mysql: InnoDB: file read of page 515891.

mysql: InnoDB: Your database may be corrupt, or you may have copied the InnoDB

mysql: InnoDB: tablespace but not the InnoDB log files.

mysql: InnoDB: in InnoDB data dictionary has tablespace id 423,

mysql: InnoDB: but tablespace with that id or name does not exist. Have

mysql: InnoDB: you deleted or moved .ibd files?

InnoDB: Ignoring the redo log due to missing MLOG_CHECKPOINT between the checkpoint 1613094601 and the end 1613094400.

[ERROR] InnoDB: Expected tablespace id 181 but found 56602 in the file ./user_databasename/table_name.ibd
[ERROR] InnoDB: Table `user_databasename`.`table_name` is corrupted. Please drop the table and recreate.

[Note] Recovering after a crash using tc.log
[ERROR] Can't init tc log

If you suspect that you have some corruption, it's likely because either you're noticing mangled data or data that no longer exists. It can also be caused since MySQL service refuses to start, but the critical point is to locate more details of such in your error logs. While the records can lead to an investigation, they are usually an immediate indicator of problems.

More information on MySQL Database Innodb recovery:

https://forums.cpanel.net/resources/innodb-corruption-repair-guide.395/

An additional helpful resource is the official InnoDB Troubleshooting documentation on the MySQL documentation site, found here:

https://dev.mysql.com/doc/refman/5.6/en/innodb-troubleshooting.html

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Thank you for your understanding,