CCTV Test: WD Purple HDDs
As the need for credible video storage intensifies, demand increases for HDDs which offer good capacities, high performance and which can cope with the rigours of constant video recording. The Purple range from WD is claimed to offer all of this, so in the past 12 months, Benchmark put a number of the drives through their paces.
When Benchmark decided to take a closer look at the WD Purple hard disk drives (HDDs), it was decided that a long-term test was the only way to assess the drives in comparison to others used in mainstream DVRs and NVRs. Taking any drive – even one claimed to be unsuitable for video surveillance – and running it for a few weeks was unlikely to tell us anything about its long term performance.
On paper, WD makes a strong case for the Purple range of drives being superior to typical HDDs found in some DVRs and NVRs.
Surveillance demands that video data is constantly written to the drive, sometimes for 24 hours a day, seven days a week. The loads are the HDDs are far higher than anticipated in a desk-top application.
The drives were tested in what were, admittedly, challenging situations, and whilst our approach breached best practice, the scenarios were designed to highlight typical issues found in many real-world applications.
Conditions were deliberately exaggerated in order to accelerate any issues or degradation with regard to performance. Despite this, we still expected to have to wait before any difference became obvious.
In a test where the drives were used in a hot area with insufficient ventilation, with ambient temperatures of around 40 degrees C, it took a mere three weeks before the mainstream AV HDDs started to misbehave, and a few weeks later we saw failures. The Purple drives, however, continued to operate as specified, and indeed they still do today.
Vibration and shock are the enemies of HDDs, and over the years we’ve seen more errors caused by machines being moved or jolted when running. Whilst PCs face similar risks, the ‘always-writing’ aspect of surveillance makes things fraught.
As with the heat tests, accelerated vibration tests saw typical AV drives fail prematurely, with a worst-case scenario where a drive failed after seven months in use. When you consider the costs not just of replacements, but of service calls to replace the items, it’;s not a good outcome. The WD Purple drives, however, continued to function.
Recording remained accurate, and we could see no indications of data loss, corruption or a reduction in performance.
Finally, Benchmark makes use of a number of small servers for various test purposes. One of these was equipped with WD Purple drives. Whilst these servers are constantly in use, they tend not to be subject to the conditions we deliberately created for the other tests.
Due to several upgrades being carried out with regard to test systems, a number of the hardware devices are being replaced. It was therefore decided to carry out a health-check on all of the HDDs currently in use to ascertain whether any legacy HDDs could be retained.
Of all the drives tested, only the WD Purple HDDs were flagged as being suitable – in terms of current performance – to be retained for use in the new systems.
The WD Purple HDDs aren’t going to make your video system any better. However, they will deliver consistent performance, they will offer a good lifespan, and they will save you time and money. For us, that’s enough!