Writes a bit for every 512 bytes in the page
- Detects when a page was not successfully written to disk
- Does not detect if all bytes were written accurately
Calculates a checksum value before passing data to the IO system (which then writes data to the disk).
- Guarantees that SQL Server had no part in corrupting the page.
- Detects corruption (by IO system) when page is read from disk.
- Checksum error (824) will be generated if data differs.
Ref : Whats best: Torn Page Detection or Checksum?