RAID Performance Tips — Maximize IOPS and Throughput
A well-tuned array can feel dramatically faster. These tips focus on practical, low-risk changes you can make, then validate with the RAID Calculator.
Pick the Right RAID Level
RAID 0 provides the highest throughput, but no redundancy. RAID 10 balances fault tolerance with excellent random IOPS. RAID 5 and 6 are efficient for capacity and reads, but parity math adds write overhead.
Use Matched, Enterprise-Grade Drives
Mixed sizes waste capacity. Mixed performance characteristics create hotspots. Prefer NAS or enterprise HDDs or SSDs, and keep firmware consistent across the set.
Stripe Size and Workload
Larger stripes favor large sequential workloads, like media. Smaller stripes help random workloads, like small database pages. Your controller or software RAID docs recommend defaults; benchmark to confirm.
SSD Caches and Write-Back Policies
Read caches help hot sets. Write-back caching improves latency, but requires power-loss protection to avoid corruption. Follow vendor guidance for battery-backed or supercap modules.
Benchmark and Monitor
Use repeatable tools (fio, CrystalDiskMark) and monitor SMART stats. Change one variable at a time. Keep notes so you can reproduce improvements.