The demands on video surveillance systems have grown dramatically in recent years. Improved video quality, higher frame rates and the need for longer retention periods for recorded video have led to a significant change in the storage that video surveillance deployments require.
While most security practitioners focus on the capabilities of the surveillance camera or the VMS, the biggest item in any modern deployment is often storage. In fact, 1/3 to 1/2 of the rising cost of surveillance typically is from this decidedly unglamorous component.
The laws of probability related to disk drive life spans and actual history both reflect that about 50 percent of DVRs can be expected to experience failures and video loss during their lifetime. To address this reality while reducing costs, some storage vendors now offer external DVR upgrades. The best of these support even small CCTV systems with just one or two DVRs for less than the cost of adding an additional DVR. They also eliminate the risk of lost video, support the maximum frame rate/resolution provided by the attached cameras and DVRs, and extend the recording capacity of multiple DVRs.
Growing Storage Needs
Nowhere is there more demand for high-volume storage than in the growing IP world. Megapixel cameras, video analytics and video management systems have resulted in dramatically improved video imagery with a requirement for longer retention periods at a higher resolution and frame rate.
Most security practitioners have addressed this by one of two approaches: They purchase commodity off-the-shelf application servers to host a VMS, and plug storage into that commodity server; or, they opt to go with the newer concept of shared, external IP storage. Let’s look at how these approaches and the storage used differ.
First, not all storage is created equal. Just as cameras differ in performance and capabilities, so does storage. Those coming from the security world often think of storage simply as commodity disk drives inside or external to DVRs, NVRs and servers. Those with an IT background typically think more in terms of shared, clustered storage savings and benefits common to data centers. Both views have merit, but neither is complete.
Most DVRs and many NVRs feature consumer- or PC-grade disk drives. They are designed for typical desktop applications like word processing, e-mail and Web browsing. More expensive are server- or OEM-grade drives, designed for more demanding workloads and with increased reliability and longer expected service lives without failures. These are the drives typically found in IT storages in data centers, but not in DVRs.
But the real difference in storage is not the disks, but in overall design. What the storage system is designed to do, how it is managed and how it is used are each much more important than the individual components.
The largest user of storage systems today is IT. Data centers employ skilled IT storage professionals to design, administer and maintain their storage systems. Frequent, scheduled system downtime is required to allow maintenance such as applying software updates, tuning performance and defragmenting the storage itself — and many are designed to operate only in climate-controlled data centers.
Unfortunately, this is not often the model in security. Security practitioners do not want to become storage experts, nor do they wish to frequently bring their systems down for maintenance. Instead, the best video-optimized solutions are designed to setup quickly and easily in just a few minutes, and then to run unattended with e-mail notification of system problems. And instead of a large data center with environmental controls, security systems are often found in cramped security rooms, tight wiring closets or on/under desks.