Performance Analysis
Why is SSD performance often stated not only as sequential read bandwidth (MB/s) but also as 4 KB random-read IOPS (I/O operations per second)?
- AIOPS expresses SSD capacity
- BSSDs cannot perform sequential reads
- CWorkloads such as databases and operating systems issue huge numbers of small reads and writes to scattered locations, so operation count determines performance
Show answer and explanation
Answer: C. Workloads such as databases and operating systems issue huge numbers of small reads and writes to scattered locations, so operation count determines performance
Reading large files such as videos is governed by sequential bandwidth. Databases and operating systems, however, read and write huge numbers of small, roughly 4 KB pieces scattered across the drive. Here per-operation latency and how many requests can be served concurrently matter, and bandwidth figures alone cannot judge performance. The same SSD can feel very different depending on the workload.
- A. It is operations per second, not capacity.
- B. SSDs can read sequentially.
- C. Correct. Comparisons must use metrics suited to the workload.