RAID Troubleshooting — Common Problems and Fixes
When something goes wrong, move methodically. Protect data first, then restore redundancy. Use vendor tools, verify hardware, and test before returning to production.
Degraded Array
A disk dropped out, or SMART shows pending failure. Replace with a same-size or larger disk, then rebuild. Avoid heavy writes until resilience returns.
Slow Rebuilds
Large HDDs, parity RAID overhead, or busy workloads extend rebuilds. Prefer maintenance windows. Consider RAID 6 or RAID 10 for safer rebuild characteristics.
Performance Dropped
Look for mixed drives, thermal throttling, controller limits, or mis-sized stripes. Benchmark before and after changes.
Array Not Detected
Check power, cabling, HBA/RAID firmware, and BIOS. If moving disks to new hardware, match controller models and firmware.