As we stated earlier, WD considers each test case a pass if the idle time is greater than 20%.
For this round of benchmarks, we considered three different cases. The first was 16 cameras running at 720p/30 FPS, adding up to slightly less than 6 Mb/s per stream in both directions for 16 cameras using H.264 compression. Only the WD Red was unable to keep up with the workload. And now we can start to see the difference WD's AllFrame technology brings to the table. While the Purple idled nearly half of the time, the Surveillance HDD was idle less than 30%. Surprisingly, the Savvio 15K.3 ended up in the middle of the pack. We reran the test multiple times, but recorded the same result.
The next test case was 16 cameras at 1080p/20 FPS. The lower frame rate was a limitation of WD's benchmark, and not a conscious decision on our part. This equals a per-stream bit rate of nearly 8 Mb/s. And we can already see the limitations of both surveillance-oriented drives. Only the enterprise disks were able to get above the 20% mark; WD's Re falls just short.
Finally, we expanded the first test case from 16 to 32 cameras, at which point all of the drives land under the pass/fail criteria. Seagate's Savvio put up a good fight, but was only idle 9% of the time.
This is, by far, the most strenuous test for these drives. Even though the bit rates aren't very high, the read/write cycles put a damper on their performance.
- Introducing Surveillance-Specific Hard Drives
- Western Digital Purple
- Seagate Surveillance HDD
- How We Test Surveillence HDDs
- Results: Transfer Rate And Access Time
- Results: WD Surveillance Benchmark, Idle Time
- Results: WD Surveillance Benchmark, Read Completion
- Results: WD Surveillance Benchmark, Distributions
- High-Capacity Hard Drives Built With Surveillance In Mind