28/10/2026
A drive fails in a RAID 5 array. During the 15-hour rebuild, a second disk throws an unrecoverable read error. Your entire array is gone.
On paper, RAID 5 looks like a smart compromise for extra capacity. In reality, rebuilding multi-terabyte drives hammers the surviving disks right when they are most vulnerable. If a second drive gives out during that long read window, you lose everything.
Write performance is an even bigger trap. Running a busy database on parity RAID forces the controller into four physical I/O operations for every single write. While a simple static site barely touches the disk, transactional workloads stall out trying to compute parity math under load.
We broke down the actual IOPS math for real production workloads. Here’s when a standard RAID 1 mirror is plenty, why databases require RAID 10, and where RAID 6 actually makes sense.
Read the full guide: https://eu1.hubs.ly/H0yC-720