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Comparison of NVRs, edge storage, and cloud storage

Comparison of NVRs, edge storage, and cloud storage

Back then, analog cameras were connected to DVRs, but the migration toward network-based cameras is followed by the migration of video recording media to digital hard disk drives. These options include PCbased NVRs, standalone NVRs, edge storage, and cloud storage. In line with this growing trend, IMS Research (an IHS company) had forecasted that network storage will account for over 30 percent of world video surveillance storage revenues in 2013. As the second half of the year progresses, the market will bear witness to this development.

Selecting the optimal storage option is crucial. “A properly designed storage system built for the unique requirements of IP video surveillance can offer a more robust, scalable, and cost-effective solution. Additionally, a properly designed storage sub-system can help customers take full advantage of the benefits of higher resolution and real-time video produced by today's advanced IP cameras,” stated John Minasyan, Senior Product Manager of IP Video Management Systems at Pelco by Schneider Electric.

NVRs can be either PC-based or standalone. Storage technology can be chosen freely from different storage systems supported by either Microsoft Windows or Linux. This allows the system integrator or end user to choose the storage system that best fits their needs and budgets. NVRs are scalable and expandable to storage demands, and performance of the storage system can be tailored to the exact needs of the surveillance system. Finally, storage redundancy technology can be used to ensure that the storage system is always online and that recorded data is not lost.

“NVRs are best deployed by organizations that possess IT skills, and have the resources and network infrastructure. Organizations that regularly purchase network equipment and have established relationships with IT providers can leverage buying power, share resources, and expertise,” noted Mike Scirica, VP of Marketing and Sales at WavestoreUSA.

There are a number of circumstances when video will fail to record. For example, at the front end, video will not be recorded if the connection to the camera is down. Neither will video be recorded if the recording or storage solution is down at the back end, which might occur due to a system failure or routine maintenance. There are, however, failover recording solutions to protect against this.

Edge storage is recording at the edge of the Ethernet network as opposed to transporting the data across the network to a centralized NVR. Essentially, the concept is the ability to decentralize storage and disperse them amongst cameras. It works by recording video directly to a storage device such as an SD/SDHC card inserted into the cameras, built-in flash memory or small hard drives. Edge storage brings another option to the possibilities of surveillance architecture. “By supporting low-bandwidth monitoring with highquality, local recordings, users can optimize bandwidth limitations and still retrieve high-quality video from incidents for detailed investigation,” said Jarmo Kalliomaki, Product Manager at Axis Communications.


The three main benefits of edge storage are: decentralized storage,redundancy, and low bandwidth. Decentralized storage eliminates the need and cost for an onsite server, NVR or PC for recorded video. It provides failover recording if the camera loses connection with the central server.

Some argue that edge storage can be unreliable as cameras can fail or be stolen. If all recordings are stored within the camera, that inevitably means all recordings would be lost. Moreover, “there is a limit to the capacity of video recordings in edge storage, such as seven days or even less, depending on SD card capacity and recording settings," said Evelyn Kao, Product Manager of Surveillance Business Division at QNAP Security. "Hence, this option may not be entirely suitable for applications where the law may require video storage for up to 30 days. Also, end users are often unaware that SD cards have a lifespan and when that is up, video will not be recorded. Unfortunately, they often only realize after an event that video had failed to be recorded."

Other disadvantages include not being able to view recorded video from the camera if there are interruptions to the network connection, not being able to control video recording via a central recording server, and possible challenges in terms of integration with third-party solutions, such as access control or building management to control recording based on events. Also, if there are numerous cameras, retrieval, playback of recordings, and investigation may be slower and it is more cumbersome to have to retrieve storage from multiple locations.

Cloud storage is often offered to the market in the form of Video Surveillance as a Service (VSaaS). This service allows end users to eliminate hardware investment because video and audio is stored and recorded in the cloud. “VSaaS is a purchased service with a periodic fee to the video service provider. On the other hand, the investment for the cameras and internet traffic demands are reduced. The maintenance and storage is outsourced to the service provider,” said Kalliomaki.

According to a new research report from TechNavio, the market growth for VSaaS is forecasted to grow to US$1.6 billion by 2016, driven by video analytics software offered by vendors. The inclusion of video analytics software will increase the value proposition of VSaaS.

However, opinion on cloud storage is divided. Although low upfront investment and low maintenance costs are appealing to many residential and smaller businesses, many security industry players feel that cloud storage is more suited to smaller-scale, non-high security applications. “VSaaS is more popular with residential and smaller business customers, as it provides the flexibility of remote management, yet the security of data and bandwidth challenges remain issues for medium to larger organizations where security is often mission critical,” noted Brian Song, MD of IDIS Europe.

"There's the issue of introducing third party cloud storage, and right now, there seems to be a skepticism regarding storage of private and potentially sensitive image data with a service provider,” added Song.

Bandwidth still has its challenges, especially when end users require full HD real-time monitoring and recording. For such requirements, “each camera needs to transmit more than 20 Mbps and even though networks can support 1 Gbps, image data can only transfer at around 600 to 700 Mbps, so potentially end users are restricted to a maximum of 35 cameras in the cloud and that is when network is optimized,” commented Song on bandwidth requirements of network cameras.

With current technology, there are now several ways to store recorded audio and video:
*  Centrally in the surveillance system's recording servers using a dedicated storage system, whether server-based, PC-based, or standalone NVRs.
* At the edge of the surveillance system in the cameras' onboard storage device.
* A combination of edge storage and NVRs.
* Cloud storage.
* A combination of NVRs and cloud storage.

An experienced system integrator would be able to assist end users in their storage selection. Budget, features, requirements, scalability, and reliability are all important considerations. The weight of each of these considerations will decide the storage option or combination of storage options.


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