How We Test Surveillence HDDs
| Test Hardware | |
|---|---|
| Processor | Intel Core i7-3960X (Sandy Bridge-E), 32 nm, 3.3 GHz, LGA 2011, 15 MB Shared L3, Turbo Boost Enabled |
| Motherboard | Intel DX79SI, X79 Express |
| Memory | G.Skill Ripjaws Z-Series (4 x 4 GB) DDR3-1600 @ DDR3-1600, 1.5 V |
| System Drive | Intel SSD 320 160 GB SATA 3Gb/s |
| Host Bus Adapter | LSI SAS 9300-8e |
| Tested Drives | WD Purple 4 TB: WD40PURXSeagate Surveillance HDD 4 TB: ST4000VX000 |
| Comparison Drives | WD Red 4 TB: WD40EFRXWD Se 4 TB: WD4000F9YZWD Re 4 TB: WD4000FYYZSeagate Savvio 15K.3 146 GB: ST9146853SSSeagate Enterprise Performance 10K HDD v7 1.2 TB: ST1200MM0017Seagate Constellation.2 1 TB: ST91000640NS |
| Graphics | AMD FirePro V4800 1 GB |
| Power Supply | OCZ ModXStream Pro 700 W |
| System Software and Drivers | |
| Operating System | Windows 7 x64 Ultimate |
| DirectX | DirectX 11 |
| Driver | Graphics: AMD 8.883 |
| Benchmark Suite | |
| HD Tune 2.55 | Block = 8 MB |
| WD Surveillance Benchmark | 16 Cameras x 720p x 30 FPS16 Cameras x 1080p x 20 FPS32 Cameras x 720p x 30 FPS |
Testing a surveillance drive should be different than running a normal consumer or enterprise drive through its paces. Because the workload is so narrowly defined, we chose only tests that would mimic a surveillance environment. As a result, you won't see typical consumer or enterprise tests, such as SYSmark or enterprise server profiles in Iometer.
One test that we did include was provided to us by Western Digital. You know that we wouldn't accept tests or scripts directly from manufacturers without fully vetting them, and we've seen enough from this one that the results appear in line with other tests and our expectations. It should be stated, however, that WD's Surveillance Benchmark directly aligns with the type of transfers that WD is targeting with the Purple. The total workload is calculated by using the following equation:
Total Workload = (# of cameras) x (bit rate per stream) x 2 (for simultaneous record and playback) + (non-AV data)
The sizes of the read and write commands are matched with the host buffer sizes for each stream. Based on industry input, WD chose a medium-sized host buffer that correlates to 1024 sectors for write commands and 768 sectors for read commands. Non-sequential, non-AV data is injected in the write commands on a per stream basis.
The result of the test is a histogram showing what percentage of the read/write commands completed within a certain period of time. The test also displays the total drive idle time. According to WD, so long as idle time is greater than 20%, the drive passed for a given workload. Anything below that number cuts into any safety margin the system might have.
Are there any demonstrable effects on performance of having these drives in a small external raid array (of perhaps 4 drives)?
If you're going to wander into the USD1/GB+ territory, even just for informational purposes, please include an SSD in this mix to be fair. SSD performance/price just might validate people buying them for surveillance drives.
Thank you.
Indeed, or any typical Enterprise SATA model (Hitachi HUS, Seagate ES2/NS, etc.)
Come to think of it, given the consequences of not being able to identify a suspect or
obtain other relevant visual information due to dropped data, as AndrewJacksonZA
says it would be interesting to know how these drives compare to various high-capacity
SSHDs/SSDs, eg. the Seagate 4TB ST4000DX001, Samsung 840 EVO 1TB (which includes
AES), and (high-density option, power saving) the Samsung MZ-MTE1T0BW 1TB mSATA.
The higher cost/GB of these products is surely more than worth it given the intended task.
Ian.
Article idea: No offence to the writers at Tom's but this is the first interesting article I have read in a long time. Could we get some more articles like this? Maybe some articles comparing onboard Intel RAID with different popular card options? Or comparing how different drives perform in different RAID configurations and workloads? I get the feeling that these drives would perform quite differently as they are really made to work as a team rather than as solo drives.
Most of the time though, surveillance recordings are merely a nice convenience in case something goes wrong but are not considered critical outside of casinos, banks and few other (very) high security applications that have their own IT departments or dedicated vendors working on their video archival needs and are unlikely to take their hardware recommendations from enthusiast sites like THG.
I doubt any normal company would waste SSDs or 10k/12k/15k RPM HDDs on video surveillance storage. They would be more likely to use standard HDDs like WD Black / Red / Green / Blue.
I really debated on whether to include SSDs in the evaluation. The problem is that because of $/GB and write endurance, it would only make sense to use them on a smaller scale setup, which is where their benefits (simultaneous high speed IO), are greatly reduced. Also, their performance would skew the graphs to the point where it would be hard to interpret the results of the HDDs.