IOPS berechnen
70% Read / 30% Write
IOPS-Ergebnis
| Raw IOPS | — |
|---|---|
| Nutzbare IOPS | — |
| Read IOPS | — |
| Write IOPS | — |
| Write Penalty | — |
⏱️ IOPS kalkuliert? Jetzt Download-Zeiten berechnen.
Festplatten-IOPS + RAID-Level + Read/Write-Ratio → echte Performance.
| Raw IOPS | — |
|---|---|
| Nutzbare IOPS | — |
| Read IOPS | — |
| Write IOPS | — |
| Write Penalty | — |
⏱️ IOPS kalkuliert? Jetzt Download-Zeiten berechnen.
IOPS measure read/write operations per second — critical for databases and virtualization.
Write Penalty: RAID 0=1×, RAID 1/10=2×, RAID 5=4×, RAID 6=6×.
IOPS (Input/Output Operations Per Second) is the central metric for storage performance. Unlike MB/s, IOPS measures how many individual accesses a system can handle per second. For databases with thousands of small transactions, IOPS matter more than throughput.
Write Penalty quantifies the overhead: RAID 0 = 1×, RAID 1/10 = 2× (mirroring), RAID 5 = 4× (data+parity read+write), RAID 6 = 6×. At 70% reads and 4 SSDs at 180 IOPS each, RAID 5 delivers only 379 usable IOPS — the penalty turns 720 raw IOPS into less than half.
An enterprise SSD: 100,000+ IOPS. A 15k HDD: ~180 IOPS. Factor >500. RAID-6 with 6 HDDs at 180 IOPS: only 180 usable IOPS — slower than a single HDD without RAID.
Workloads are mostly read-heavy: DBs 70–90%, file servers 80%, virtualization 60–70%. The higher the read ratio, the less the Write Penalty hurts. Use the slider to match your workload.
You're planning a new database or VM host and want to know whether the planned disks are enough. Or you're facing the classic question: six HDDs in RAID 5 or rather two SSDs? IOPS is the number everyone quotes — and hardly anyone puts it in perspective. This calculator translates disk IOPS, disk count, and RAID level into one concrete, usable number you can go shopping with.
Enter the IOPS a single disk achieves — 180 for a 15k HDD, 100,000 and more for an enterprise SSD.
Choose the number of disks and the RAID level — from RAID 0 to RAID 60.
Set the read ratio of your workload (databases: 70–90%). The calculator applies the write penalty automatically and shows you the usable IOPS.
Six 15k HDDs at 180 IOPS each give 1,080 raw IOPS. In RAID 5 (penalty 4) at 70% reads, only about 568 usable IOPS remain — a single enterprise SSD easily delivers a hundred times more. Exactly these calculations save you from nasty surprises after the purchase.
Why does RAID cost so much performance? A write to RAID 5 requires four operations: read the data block, read the parity block, recompute both, write them back — hence factor 4. RAID 6 needs factor 6 because of two parities, a mirrored RAID 10 only factor 2. More parity means more protection — and fewer usable IOPS.
The gap is gigantic: an enterprise SSD achieves 100,000+ IOPS at 0.1–0.2 ms latency, a 15k HDD manages about 180 IOPS at 5–10 ms. That's a factor of more than 500. For small random accesses — the typical database pattern — the SSD wins outright. HDDs only make sense for large sequential data where throughput counts.
IOPS count operations, MB/s measures throughput. A database makes millions of tiny accesses — it starves for IOPS. Streaming (video, backups) needs throughput. A system can deliver plenty of MB/s and still choke on IOPS.
Rule of thumb: 50–100 IOPS per active connection, depending on the workload. 200 concurrent sessions mean 10,000–20,000 IOPS. That's exactly what this calculator is for: size your disks before you buy.
The overhead a RAID level causes on write operations: for every data block, parity blocks must additionally be read, computed, and written. RAID 5 costs factor 4, RAID 6 factor 6.
Yes — and they blow the scale: at 0.1 ms latency, 100,000 IOPS are normal. In SSD systems the disk is rarely the bottleneck; CPU, network, or the database itself matter more.
Background in our blog: Festplatten-Performance verstehen. Planning capacity and redundancy? Use the RAID calculator.