5 Tips on Picking the Right NAS for Your Surveillance Needs

Pssst. Hey buddy. No, you. Yeah, you. I hear you need a surveillance system. Just so happens, I got a surveillance system for you. But these are stripped down. They need hard drives. Surveillance system without a hard drive? That’s like buying a car with no engine. You’ve got to have hard drives. You’ve got to have storage.

Buying a surveillance system doesn’t have to be a shady deal, as long as you know what you need. WD learned that a great opportunity exists between surveillance-kit manufacturers and its line of hard drives. After all, the amount of data that you need to store from surveillance can quickly fill a 4TB hard drive. This chart shows the approximate amount of data that a hard drive holds (although individual usage may vary), so if you’re thinking of purchasing a surveillance system with limited drive space, you’re ultimately doing yourself a disservice.

There are many situations that affect the amount of video you may keep. Extended archiving is one factor. How much video would you keep (and why)? If you’re only keeping eight hours of video a day, it can take a while to fill a high-capacity drive. But if that video is of an enhanced resolution, then that increases your need for storage. A 24/7 video stream at 20 fps/704 × 480 image resolution can fill a 1TB drive in only 42 days with MPEG-4 compression. Add to that intelligent video (video streams that are enhanced, high resolution, and offer perks like facial recognition, which matches the images captured on your footage against a databank of suspected perpetrators, and then notifies law enforcement when there’s a match), and suddenly your storage needs blossom out of control. For instance, a 24/7 intelligent video stream using MPEG-4 compression at 30 fps/1280 × 1024 resolution will fill a 6TB drive in just 48 days. Encoding protocols also make a difference—H.264 encoding delivers approximately 84 days of the same quality video.

Around four years ago, many hard drive manufacturers realized the important link between surveillance and storage space, especially with the advent of better, more sophisticated and higher-resolution recording technology like high-resolution and intelligent video. We are moving past the days of fuzzy, grainy footage of possible “perps,” and more toward crystal-clear identification of people in surveillance footage (the rise in terrorism has also fueled this need for clearer imaging). We are also reconsidering using cost-based decisions for surveillance, especially now that prices on both hard-drive storage and NAS servers are finding more amenable levels among general consumers. So hard questions are being asked in the surveillance hard-drive category: should I opt for more, cheaper drives, or should I go for enterprise-level drives that cost a pretty penny but have some longevity in their arena?

WD understands this symbiosis and the need for reliable, stable media in surveillance systems. With B&H kits, the company has partnered with top security-system manufacturers such as Axis, Hikvision, and TRENDnet to pair up NVRs, cameras, and NAS servers (like WD’s DL series 2- and 4-bay servers, with Intel® Atom™ C-series processors, up to 2GB of RAM and dual Gigabit Ethernet ports). But before you leap into the deep end of buying a surveillance system, here are a few tips that will help you make the right choices.

1. Time of use makes a difference

If you’re using your surveillance for spot checks on your property, and the device is only running for a set amount of time (like after business hours only) then an enterprise drive may be more than you need. But since most businesses have their security cams running for 24/7, you need enterprise-level drives that are tested to work reliably every hour of every day. Also, desktop drives are designed to run for short periods and are not built to withstand high-vibration environments like datacenter server systems or Surveillance NAS arrays.

2. Lower power consumption is important

When you’re looking at high-performance, low-latency drives, you should make less consideration for speed and more for performance. Why is that? Because the drives are running continually all night and day, you don’t want heating issues. Consider drives that run something like WD’s Intelliseek technology, which increases or decreases seek speed in accordance with usage. So if you see 5400 rpm drives and you feel a 7200 (or even 10000) rpm drive might be better, think again—a higher rotational speed may lead to critical failure points when heat levels are maxed (and those will occur faster and more often in higher-speed drives).

3. There is a difference between a surveillance drive and an enterprise drive

Most companies will advertise that their “enterprise”-level drives are great for all 24/7 operations. That is not always so. Surveillance drives are optimized for multiple data streams but don’t fix errors on the fly—like most enterprise level drives do. Why is that? An enterprise-level drive used in a server situation is storing, moving, archiving, and processing information and should do so without error to prevent data loss and drive malfunctions, and it does this by correcting small errors as they are caught. A surveillance drive will optimize video streaming, without worrying about (what it considers) small bit-error corrections.

4. The NAS processor makes a difference

For NAS surveillance, you need a processor that can handle video files effectively; too low, and you’ll drop frames or the footage will stutter. Most media servers benefit from a more stable processor because they lean heavily on the READ function when streaming, but a surveillance NAS also needs to rely on a heavy WRITE function, as well. Try to stay with at least a dual-core (quad-core is better) x86 CPU at the least, with 2GB of RAM. Money too tight? You could try an ARM v7 CPU with 1GB of RAM, but you’ll see the difference. And if what you need is reliability and error-proof surveillance, you may want to opt in for the better processor and higher RAM.

5. To RAID or not to RAID

Another important consideration is what you do with the data once you’re finished recording. Are you going to keep the footage long term? If so, and if archiving that footage is going to be a key element in your system, then you’ll want multiple drives in a RAID array. The number of drives depends on how much you plan on storing. Make sure to get drives that are hot-swappable so you can replace drives on the fly, and easily add and expand your system. RAID arrays will allow you to mirror data on a backup drive so that you will always have a copy of the footage somewhere. Hot-swapping means that as drives fill up, you can swap them out and replace them while the system is still online.

Be aware though: some surveillance storage media has a limit on the number of bays that it can access. For instance, WD Purple drives are recommended for use in NAS environments of up to 8 bays, and are optimized for up to 32 HD cameras. WD also makes specialized hard drives for use in datacenter environments that will expand those requirements. For desktop RAID and regular non-surveillance datacenter NAS servers, WD suggests WD Re drives.