Levels of Disk I/O Integrity Checking
To protect against physical data corruption, Teradata Database permits you to select various levels of disk I/O integrity checking of your table, hash index, and join index data. Secondary index subtables assume the level of disk I/O integrity checking that is defined for their parent table or join index. Furthermore, you can specify corruption checking levels at both system and table levels. These checks detect corruption of disk blocks (checksum sampling can also detect some forms of bit and byte corruption) using one of the following integrity methods, which are ranked in order of their ability to detect errors:
1 Full end‑to‑end checksums.
Detects lost writes and most bit, byte, and byte string errors.
2 Statistically sampled partial end‑to‑end checksums.
Detects lost writes and intermediate levels of bit, byte, and byte string errors.
3 No checksum integrity checking.
Detects some forms of lost writes using standard file system metadata verification.