inno corrupt

Intentionally corrupt pages in an InnoDB tablespace file for testing.

Synopsis

inno corrupt -f <file> [-p <page>] [-b <bytes>] [-k] [-r] [--offset <byte>] [--verify] [--json] [--page-size <size>]

Writes random bytes into a tablespace file to simulate data corruption. This is designed for testing checksum validation (inno checksum), InnoDB crash recovery, and backup-restore verification workflows.

Warning: This command modifies the target file in place. Always work on a copy of the tablespace, never on a production file.

Three targeting modes are available:

Header mode (-k): Writes into the 38-byte FIL header area (bytes 0-37 of the page), which will corrupt page metadata like the checksum, page number, LSN, or space ID.
Records mode (-r): Writes into the user data area (after the page header and before the FIL trailer), corrupting actual row or index data without necessarily invalidating the stored checksum.
Offset mode (--offset): Writes at an absolute file byte position, bypassing page calculations entirely. Note that --verify is unavailable in this mode since there is no page context.

If no page number is specified, one is chosen at random. If neither -k nor -r is specified, bytes are written at the beginning of the page.

Flags

Flag	Short	Required	Default	Description
`--file <path>`	`-f`	Yes	--	Path to the InnoDB data file (.ibd).
`--page <number>`	`-p`	No	Random	Page number to corrupt. If omitted, a random page is chosen.
`--bytes <count>`	`-b`	No	`1`	Number of random bytes to write.
`--header`	`-k`	No	Off	Target the FIL header area (first 38 bytes of the page).
`--records`	`-r`	No	Off	Target the record data area (after page header, before trailer).
`--offset <byte>`	--	No	--	Absolute byte offset to corrupt. Bypasses page calculation.
`--verify`	--	No	Off	Show before/after checksum comparison to confirm corruption.
`--json`	--	No	Off	Output in JSON format.
`--page-size <size>`	--	No	Auto-detect	Override page size.

Examples

Corrupt 1 byte on a random page

inno corrupt -f test_copy.ibd

Corrupt 16 bytes in the header of page 3

inno corrupt -f test_copy.ibd -p 3 -k -b 16

Corrupt the record area of page 5 and verify

inno corrupt -f test_copy.ibd -p 5 -r -b 32 --verify

Corrupt at an absolute file offset

inno corrupt -f test_copy.ibd --offset 65536 -b 8

JSON output for automation

inno corrupt -f test_copy.ibd -p 3 -b 4 --verify --json

Test-and-validate workflow

cp actor.ibd test.ibd
inno corrupt -f test.ibd -p 3 -b 4 --verify
inno checksum -f test.ibd

Output

Text Mode

Writing 16 bytes of random data to test.ibd at offset 49152 (page 3)...
Data written: A3 B1 C5 D7 E2 F0 11 22 33 44 55 66 77 88 99 AA
Completed.

With --verify:

Verification:
  Before: OK (algorithm=Crc32c, stored=2741936599, calculated=2741936599)
  After:  INVALID (algorithm=Crc32c, stored=2741936599, calculated=1084227091)

JSON Mode

{
  "file": "test.ibd",
  "offset": 49152,
  "page": 3,
  "bytes_written": 16,
  "data": "A3 B1 C5 D7 E2 F0 11 22 33 44 55 66 77 88 99 AA",
  "verify": {
    "page": 3,
    "before": {
      "valid": true,
      "algorithm": "crc32c",
      "stored_checksum": 2741936599,
      "calculated_checksum": 2741936599
    },
    "after": {
      "valid": false,
      "algorithm": "crc32c",
      "stored_checksum": 2741936599,
      "calculated_checksum": 1084227091
    }
  }
}

IDB Utils Documentation