CHFI Database and Application Forensics Practice Question

Exhibit

Refer to the exhibit.

Exhibit:
```
MySQL Error Log Entry:
[ERROR] Plugin 'InnoDB' init function returned error.
[ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
[ERROR] Unknown/unsupported storage engine: InnoDB
[ERROR] Aborting
```

Refer to the exhibit. A database administrator finds the above error log entries when attempting to start the MySQL service. The server was working fine yesterday. What is the most likely cause of this issue?

⚠ Common exam trap

EC-Council often tests the distinction between permission errors, disk-full errors, memory errors, and corruption errors, so the trap here is that candidates may confuse a 'cannot start' error with a permission issue or memory exhaustion, rather than recognizing the specific InnoDB corruption signature in the log.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

The InnoDB system tablespace file (ibdata1) is corrupted.

The error log entries indicate that InnoDB is unable to open or read the system tablespace file (ibdata1), which is the core file storing the InnoDB data dictionary, undo logs, and doublewrite buffer. A corrupted ibdata1 prevents MySQL from starting because the storage engine cannot initialize its internal structures, even if the server was operational the previous day. This matches the symptom of a sudden failure without prior configuration changes.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
The MySQL user does not have write permissions to the data directory.
Why it's wrong here
If the MySQL OS account lacked write permission to the data directory, startup would fail earlier with explicit 'Permission denied' or 'Can't create/write to file' errors when opening or creating files. Inode and file-access checks happen before InnoDB reads the system tablespace header. An InnoDB corruption error like 'Cannot open datafile' or 'Database page corruption' is not a permission complaint, so this hypothesis does not match the exhibit.
✗
The binary log is full and cannot be rotated.
Why it's wrong here
The binary log records committed transactions and is written after the storage engine accepts them; it is never read during InnoDB initialization or crash recovery. A full binary log or a log-rotation failure would generate runtime errors such as 'Could not write to binary log' or 'disk full' at commit time, not an InnoDB tablespace header failure. InnoDB recovery relies on redo logs (ib_logfile*), not binlogs, so a binlog problem cannot prevent InnoDB from loading ibdata1.
✗
The server ran out of memory due to high innodb_buffer_pool_size.
Why it's wrong here
An oversized innodb_buffer_pool_size might trigger the OS out-of-memory killer or an 'InnoDB: Cannot allocate memory' error before any tablespace file is opened. Memory allocation failures typically appear as 'Out of memory' or a process kill, not as a datafile corruption or checksum mismatch. The exhibit's error indicates a persistent I/O or integrity problem in ibdata1, not a transient memory shortage, so this explanation is inconsistent with the observed message.
✓
The InnoDB system tablespace file (ibdata1) is corrupted.
Why this is correct
The InnoDB system tablespace file (ibdata1) holds the data dictionary, rollback segments, and undo tablespaces; its first page contains a header that InnoDB validates at startup. If that header or any critical internal page is corrupted, InnoDB cannot initialize its storage engine and aborts with errors such as 'Database page corruption' or 'Cannot open datafile'. This matches the administrator's exhibit, making corruption of ibdata1 the correct explanation; recovery requires restoring the tablespace from backup or rebuilding it with new setup.

Go deeper

CHFI Database and Application Forensics Practice Question

Exhibit

Why each option matters

Option-by-option breakdown

Related to this question