RAID (Redundant Array of Independent Disks) is a method of combining multiple physical drives into one logical unit to improve performance, redundancy, or both.
The average time (in hours) a drive is expected to operate before failing. Higher MTBF means more reliable hardware.
The time required to reconstruct data on a replacement drive after a failure. Longer rebuild times increase the risk of a second failure during recovery.
A statistical estimate of how long a RAID system can operate before data loss occurs. It considers drive failures, rebuild time, and RAID redundancy. Higher MTTDL means a safer system.
The probability that a bit read from a disk will be incorrect due to hardware limitations. Even tiny BERs (like 1 in a trillion) can cause issues during rebuilds, especially with large drives.
Occurs when a drive fails to read a sector during rebuild. BER contributes to URE risk, which can compromise RAID recovery.
Total storage per drive. Larger drives take longer to rebuild and are more susceptible to BER-related errors.
The chance that the RAID system will experience data loss over a given time period (e.g., 5 years). Calculated using MTTDL and exponential failure models.