Isi Data Integrity (IDI) is the OneFS process that protects file system structures against corruption using 32-bit CRC checksums. All OneFS file system blocks, both for file and metadata, use checksum verification. Metadata checksums are housed in the metadata blocks themselves, whereas file data checksums are stored as metadata, providing referential integrity. All checksums are recomputed by the initiator, the node servicing a particular read, on every request.
If the recomputed checksum does not match the stored checksum, OneFS will generate a system alert, log the event, and retrieve and return the corresponding error correcting code (ECC) block to the client and attempt to repair the suspect data block.