Method and apparatus for maintaining reliability of a RAID

An apparatus of maintaining reliability of a mapped redundant array of independent disks, comprising:

• a first probability determining module configured to determine a first data loss probability, the first data loss probability indicating reliability of a traditional redundant array of independent disks;
• a second probability determining module configured to determine a second data loss probability, the second data loss probability indicating reliability of the mapped redundant array of independent disks, wherein each disk of a plurality of disks is divided into a plurality of disk extents, wherein the mapped redundant array of independent disks includes at least a portion of the plurality of disk extents from across the plurality of disks;
• and
• a condition determining module configured to determine, based on the first and second data loss probabilities, a condition for maintaining the reliability of the mapped redundant array of independent disks, wherein the first probability determining module is further configured to:
• determine a first relationship between a first probability for a single disk failure at any time and the number of disks in the traditional redundant array of independent disks;
• determine a second relationship between a second probability for a single disk failure within a predetermined time interval and a length of the predetermined time interval;
• and
• determine the first data loss probability based on the first and second relationships.

A computer program product for maintaining reliability of a mapped redundant array of independent disks, the computer program product comprising:

• a non-transitory computer readable medium encoded with computer-executable code, the code configured for the execution of:
• determining a first data loss probability, the first data loss probability indicating reliability of a traditional redundant array of independent disks;
• determining a second data loss probability, the second data loss probability indicating reliability of the mapped redundant array of independent disks, wherein each disk of a plurality of disks is divided into a plurality of disk extents, wherein the mapped redundant array of independent disks includes at least a portion of the plurality of disk extents from across the plurality of disks;
• and
• determining, based on the first and second data loss probabilities, a condition for maintaining the reliability of the mapped redundant array of independent disks, wherein determining the first data loss probability comprises:
• determining a first relationship between a first probability for a single disk failure at any time and the number of disks in the traditional redundant array of independent disks;
• determining a second relationship between a second probability for a single disk failure within a predetermined time interval and a length of the predetermined time interval;
• and
• determining the first data loss probability based on the first and second relationships.