Data Integrity Field
Data Integrity Field (DIF) is an approach to protect data integrity in computer data storage from data corruption. It was proposed in 2003 by the T10 subcommittee of the International Committee for Information Technology Standards.{{Cite web |title= End-to-End Data Protection Justification |work= T10 Technical Committee document 03-224r0 |date= July 1, 2003 |author= Keith Holt |url= http://www.t10.org/ftp/t10/document.03/03-224r0.pdf |accessdate= August 29, 2013 }} A similar approach for data integrity was added in 2016 to the NVMe 1.2.1 specification.{{cite web |title=NVM Express Revision 1.2.1 |date=June 5, 2016 |publisher=NVM Express, Inc. |url=https://nvmexpress.org/wp-content/uploads/NVM_Express_1_2_1_Gold_20160603.pdf}}
Packet-based storage transport protocols have CRC protection on command and data payloads. Interconnect buses have parity protection. Memory systems have parity detection/correction schemes. I/O protocol controllers at the transport/interconnect boundaries have internal data path protection.
Data availability in storage systems is frequently measured simply in terms of the reliability of the hardware components and the effects of redundant hardware. But the reliability of the software, its ability to detect errors, and its ability to correctly report or apply corrective actions to a failure have a significant bearing on the overall storage system availability.
The data exchange usually takes place between the host CPU and storage disk. There may be a storage data controller in between these two. The controller could be RAID controller or simple storage switches.
DIF included extending the disk sector from its traditional 512 bytes, to 520 bytes, by adding eight additional protection bytes.
This extended sector is defined for Small Computer System Interface (SCSI) devices, which is in turn used in many enterprise storage technologies, such as Fibre Channel.{{Cite FTP |title=Data Integrity Extension |date=May 2, 2003 |url=ftp://ftp.t10.org/t10/document.03/03-111r0.pdf |server=T10 Technical Committee document 03-111r0 |url-status=dead |accessdate=August 29, 2013 }} Oracle Corporation included support for DIF in the Linux kernel.{{Cite web |title= Linux Data Integrity Project |author= Martin K. Petersen |year= 2009 |url= https://oss.oracle.com/projects/data-integrity/ |accessdate= August 29, 2013 }}{{Cite news |title= Proactively Preventing Data Corruption |date= January 3, 2008 |author= Martin K. Petersen |work= Enterprise Open Source Magazine |url= https://oss.oracle.com/projects/data-integrity/dist/documentation/ppdc.pdf |accessdate= August 29, 2013 }}
An evolution of this technology called T10 Protection Information was introduced in 2011.[https://www.seagate.com/files/staticfiles/docs/pdf/whitepaper/safeguarding-data-from-corruption-technology-paper-tp621us.pdf Safeguarding Data From Corruption - Technology Paper]. PDF, Seagate, 2011{{Cite web |title= An Integrated End-to-End Data Integrity Solution to Protect Against Silent Data Corruption |work= White paper |publisher= Oracle Corporation |author= EMC Corporation |author-link= EMC Corporation |date= September 18, 2012 |url= https://community.emc.com/servlet/JiveServlet/downloadBody/19278-102-3-68831/h10058-data-integrity-solution-wp.pdf |accessdate= August 29, 2013 }}
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References
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External links
- [https://web.archive.org/web/20150109235547/https://oss.oracle.com/~mkp/docs/lpc08-data-integrity.pdf Linux Data Integrity], August 30, 2008, Oracle Corporation, by Martin K. Petersen (archived from the original on January 9, 2015)
- [http://mkp.net/pubs/storage-topology.pdf Linux Storage Topology and Advanced Features], November 24, 2009, by Martin K. Petersen
- [http://www.t10.org/ftp/t10/document.03/03-111r0.pdf Data Integrity Field - T10.org], working on Feb 15 2019.