Xoralgo

Founded on May 8, 2018, Xoralgo builds the next generation RAID (Redundant Array of Independent Disks). While the cornerstone of the current RAID systems is the aging RAID 6, our RAID is based on a new algorithm utilizing five redundant disks. Our technology is called PentaRAID™.

News

The USPTO grated the US utility patent behind the Xoralgo technology! The U.S. patent number is 10,997,024 [Application Number 16/521,256] and it was granted by the patent office on 2021-05-04 for method and system utilizing quintuple parity to provide fault tolerance. All claims of the original application were approved!

The problem we address

A famous data loss study at CERN exposed data loss due to reasons other than an apparent disk failure. In particular, errors that RAID 6 cannot correct (dual bit errors). The CERN study have been confirmed by others. Before PentaRAID™ this and other problems (such as UDE) were too costly to address. Now there is a solution.

The main limitation of RAID 6 is that it uses only two redundant disks. This makes it vulnerable to data loss. One cause of data loss is a catastrophic disk failure. Another cause of data loss gaining importance today is silent data corruption due to undetected disks errors (UDE). UDE are a product of laws of physics and do occur during "normal" disk operation. In the era of huge disk drives, a UDE may occur every few hours. The IT departments often refer to UDE as " bit flip " as indeed a UDE may occur as a result of repeatedly reading a bit of data from a disk. Every 1014 reads or so, the bit will be read incorrectly, and this error may propagate in calculations (such as calculating the total of a giant spreadsheet), rendering the entire calculation invalid.

The inadequacy of RAID 6 is well-known. The failure of one disk requires its replacement and reconstruction of the data. This process may take days or weeks for the typical multi-terabyte disks of today. The RAID operating with failed disks is said to be in degraded mode. Thus, RAID systems of today spend a significant amount of time operating in degraded mode. RAID 6 in this mode can detect UDE, but cannot correct them, thus resulting in data loss.

It is not unlikely that a second disk fails during the recovery of the first failed disk. This results in doubly degraded mode. While no data loss is imminent for a RAID 6 system operating in doubly degraded mode, in this mode RAID 6 is not capable of detecting or correcting any errors. Thus, any UDE remains undetected and uncorrected by a RAID 6 operating in doubly degrated mode.

RAID 6
A common RAID 6 configuration. Source: en:User:Cburnett, RAID 6, Converted to Inkscape 0.92, CC BY-SA 3.0.
PentaRAID