Western Digital Purple Surveillance Storage 4TB HDD Review

Introduction

In small towns and large cities all over the world, surveillance is on the rise. I'm not talking about large scale government eyes, but rather surveillance on a much smaller scale. Just weeks ago in the small town I live in, where it's rare to find a locked door, a home was burglarized. Surprisingly, this was almost a life-changing event here, something on the local timeline because crimes with victims are rare here. The burglary made state news with coverage in the statewide newspaper and television broadcasts because the homeowners had a video surveillance system. Three unmasked men will spend the next twenty years behind bars thanks to the video evidence, and this small town can go back to peaceful living.

Visit any police department's Facebook page and you'll see endless still images of video footage capturing people doing bad things. Sometimes the raw video is grainy, black and white, or missing frames. Surveillance systems can be complicated, requiring some skill to configure properly, and the number of sub-par prepackaged systems on the market outnumber quality systems designed and installed by professionals.

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Western Digital recently released a new product that helps to take the guesswork out of video surveillance. The company added a new color to their HDD product family, but WD Purple is more than just a physical hard drive with features for surveillance installers. On the Purple product pages, installers can calculate the storage amount needed for a system.

Another built-in feature helps guide installers on which Western Digital HDD model works best with a given system. In larger systems with eight or more drives, Western Digital recommends either a Se or Re product taken from the enterprise product line up. The new Purple, like the Red model for NAS products, is a lower price unit designed for smaller system that do not require the full gamut of enterprise features.

Specifications, Pricing, and Availability

Available in four capacity sizes, 1TB to 4TB, Purple drives bring surveillance-specific features to the market at a lower price than Western Digital's enterprise offerings. Designed for use in tabletop applications like the QNAP VS series with advanced surveillance features enabled, the secret sauce in this product is the firmware features that support up to 32 HD channels of recording.

Western Digital calls the new firmware feature AllFrame Technology.

Key benefits:

• Reduces video frame loss with surveillance-class storage.
• Specifically tuned for surveillance security systems.
• Caching algorithms are tuned for write-intensive, low bit rate, high stream count applications that are typical of surveillance applications.
• Priority change for write allocations and preemptive caching policies.
• TLER & ATA streaming support.
• Supports up to eight drives.

Western Digital also claims that Purple drives uses less power than competitors' surveillance products, but the claim was made before Seagate's latest surveillance product announcement, which came just one day before the Purple drive announcement.

Newegg already lists Purple SKUs and prices, but at the time of writing, the drives were out of stock. The top-tier model is the 4TB drive andoffers up to 32TB of capacity when configured with the maximum drive count of eight. In RAID 5, that would drop to 28TB of redundant storage. According to Western Digital's Capacity Selector tool, that is enough for 16 cameras recording at 1080p with 12 frames per second and storing the data for 30 days.

The Purple products ship with a three-year warranty.

PRICING: You can find the Western Digital Purple (3TB) for sale below. The prices listed are valid at the time of writing but can change at any time. Click the link to see the very latest pricing for the best deal.

United States: The Western Digital Purple (3TB) retails for $141.53 at Amazon.

Canada: The Western Digital Purple (3TB) retails for CDN$187.76 at Amazon Canada.

Western Digital Purple 4TB HDD

On the outside, there isn't a lot to look at with the drive. It's a 3.5-inch form factor SATA drive that isn't much different physically from the Green or Red products.

Benchmarks - Test System Setup and Base Performance

Desktop Test System

HD Tach Sequential Performance

Although not designed for desktop use, we still wanted to run a couple of tests to get a better understanding of how AllFrame Technology works. Right at the start, we noticed a difference in the way the drive reads and writes sequential data. Normally with HDDs, we see a curve with the drives performance dropping off significantly as the heads move from the optimal area on the platter.

With the Purple, we see the read performance start to drop off but then increase again. The write speed doesn't drop off like an HDD at all. The write test reminds us of what we see testing SSDs in a degraded state.

AIDA64 64KB Latency

Read Latency 64KB

Write Latency 64KB

The large 64MB buffer keeps the latency steady while reading and writing the span of the drive.

Benchmarks - Surveillance Test Tool

Surveillance Test Tool

Version and / or Patch Used: 1.00

WD provided a test tool for measuring Command Competition Time (CCT). The tool shows the percent of commands completed in millisecond blocks of time. Ideally, you want all of your commands to complete in the least amount of time. Although we're showing both read and write tests on the chart, surveillance systems spend over 90 percent of the time writing data and less than 10 percent reading it back.

HD Tach - CCT 720P 8-Channels

HD Tach - CCT 720P 16-Channels

HD Tach - CCT 720P 32-Channels

It isn't until we reach the final test with 32 channels that we see a significant change in the chart. The change comes in the read performance where the single drive shifts the CCT to the 20 to 40ms range. In all of the tests, 99 percent of the writes occur in the 0 to 5ms period.

Final Thoughts

Like the Red series before it, the new Purple series brings peace of mind when configuring a specific application system. Right out of the box, end users know that the drives work in the application and have the features needed to make a successful project. Also like the NAS market, the surveillance market should grow considerably over the next decade. Given what is on the line when surveillance comes into play, it's nice to see Western Digital taking the guess work out of choosing a drive for this market.

Looking over the market for other products used in surveillance applications, the Purple series fairs well with pricing. The model we tested today, the 4TB Purple, is less than $190 at Newegg but is currently out of stock. The 3TB model at $139.99 matches the price of the WD AV-GP, the company's previous surveillance HDD.

With the projected growth of this market and the need for easier to configure systems, Western Digital has provided a necessary tool for making a complicated task easier.

PRICING: You can find the Western Digital Purple (3TB) for sale below. The prices listed are valid at the time of writing but can change at any time. Click the link to see the very latest pricing for the best deal.

United States: The Western Digital Purple (3TB) retails for $141.53 at Amazon.

Canada: The Western Digital Purple (3TB) retails for CDN$187.76 at Amazon Canada.