This article originally appeared in the August 2012 issue of SD&I magazine
In today’s market video surveillance data is more valuable than ever. Surveillance is moving beyond cost-oriented security and to revenue-producing business functions such as optimal staffing, customer service training and buying pattern analysis. The availability of rich video data is made possible by the widespread adoption of IP megapixel cameras along with video analytics that can convert everyday video into ‘intelligent’ video streams. The impact of these technologies on video storage systems is dramatic: the detailed imaged quality generates huge requirements for storage capacity and bandwidth while the security and business analytics push systems to deliver low latency read-and-write operations.
As more security systems embrace IP infrastructure, storage platforms are evolving to meet the fast ingest requirements and analytics needs. This is a decidedly different design target than conventional storage systems designed for IT applications. Flash memory is one technology— commonly seen in the consumer market in iPods, digital cameras and mobile phones—that increased the development and adoption of portable devices. As with so many consumer innovations, flash can be opportunistically applied to markets where high-volume consumer scale economics make the technology useful and cost-effective. There is exactly such an opportunity in applying flash technology to the storage systems used in video surveillance.
How flash translates into surveillance
Flash is chip-based storage technology that can be more than 100 times faster than common hard disk drives. Read and write times vary by device but flash is particularly effective at eliminating the spin-up time of traditional mechanical disks that can slow read and write times. In addition, flash devices minimize mechanical frailties of a spinning disk drive and are less likely to break when a unit is dropped or damaged.
Today, flash technology use in video surveillance is limited because the price of flash devices is much higher than traditional hard disk storage. For example, a 1TB Enterprise SATA drive costs approximately $100 while a 1TB flash drive appropriate for video surveillance runs 10- to 50-times more. That adds up in a hurry since megapixel cameras can consume 1TB of capacity in a day. And the cost impact of using flash in this way on a large installation would be monumental. For a mid-sized airport, the use of flash as primary storage would add more than $500,000 to the storage budget. Because of the common budgetary restrictions found in this space, it is clear that flash will not replace cost-effective disks as the storage technology of choice.
One new approach introduces flash memory not as a primary storage replacement but as an accelerator for speeding writes into relatively slow disk drives. This “Flash Acceleration” concept inserts a small amount of flash, typically less than 1 percent on a capacity basis, in front of disk drives to speed disk write speed dramatically but at a minimal cost. Because flash retains data if power is lost, it also eliminates the need for maintenance-intensive batteries typical in conventional IT storage systems.
The flash acceleration approach becomes even more attractive for surveillance when applied to appliance systems where the benefits of flash can be spread across hundreds or thousands of video channels. This allows the system performance to scale at flash speeds while the cost trends with cost-effective hard disks. It also allows the cost and performance to scale with the number of high-resolution cameras since the application of flash scales with storage appliances.