Security video surveillance system can be divided into different parts, and different parts have their unique storage needs. Data acquisition - the front end of a security monitoring system, the camera. The most common type of storage is Flash (Flash)/ SD CARDS, which typically hold around 256GB.

Edge segment - typically an NVR connected to the camera and an external disk array or NAS. The storage medium used in this part is usually a hard disk, and the capacity varies from 3TB to 10TB, depending on the number of connected cameras and the quality of the video. Some NVRS have AI recognition functions, which can preliminarily analyze video collected on site and alert. Therefore the storage hard disk read and write speed and capacity must meet the requirements in this respect.

Data center - it is mainly used to archive video for a long time and analyze video in detail with big data tools. This section will use different types of hard drives, with video archiving using extra-large hard drives, and big data analysis using high-speed or near-line enterprise-class hard drives. So how do you build the right storage solution for the security system? Informal estimates put the number of surveillance videos produced by global surveillance systems at about 560 petabytes (1 petabyte =1,000 terabytes) a day, rising to 2,500 petabytes a day by 2019. In 2023, up to 3,500 petabytes of surveillance video will be produced every day.

Has boosted the number of surveillance cameras - campus shooting from the United States to bring security risks to the wisdom of the Chinese urban construction has boosted the number of surveillance cameras, surveillance video obtained as more and more high - from 720 p to 1080 p or even super clear 4 k video are greatly increased the video files, monitor video retention period longer - may be based on the cause of the safety risk increase or the popularity of artificial intelligence analysis, general surveillance video pre-approved is longer than the past.

In any case, we must anticipate the storage capacity requirements of a video surveillance system before planning or purchasing a storage hard drive. You need to know: the number of cameras, how many frames per second of video, the length of a day of shooting, video retention time, resolution, video quality, and compression methods (MJEG, h.264, h.265). For example, 10 cameras shoot at 15 frames per second, 1080p resolution, 24 hours per day. If the video retention period is 30 days, the storage space requirement of MJPEG video is 100TB, h. 264 compression is about 5TB, and h. 265 compression is about 3TB.

The biggest difference between the hard disk of surveillance video and the hard disk of general desktop is the asymmetry of reading and writing data. The hard disk of surveillance video generally writes a lot of data and reads relatively little. The number of NVR connected cameras ranges from a few to dozens and the working hours are most likely 7 days x24 hours without interruption. As a result, the hard drive's control firmware must be optimized to distribute the cache more efficiently, allowing video data from different cameras to be written to the hard drive quickly and uninterruptively.

Another parameter to watch out for is the "annual workload" - typically a read-write optimized surveillance video hard drive can provide 180 terabytes of workload per year. When purchasing a hard drive for surveillance video storage, it is important to pay attention to whether the storage capacity is sufficient, how many channels can be supported by hd cameras, and whether the annual workload parameters (TB/ year) can meet the demand.

Video monitoring hard disks are typically installed in slots on NCR/DVR, NAS, or external disk arrays. Because mechanical hard disk will produce certain jitter in the working state, in the working environment of multiple hard disks, the jitter will overlap and affect the accuracy of hard disk reading and writing. Serious cases can lead to errors in the data writing process and may even corrupt the recorded data. As a result, video surveillance hard drives are equipped with rotating vibration (RV) sensor technology to compensate for vibrations caused by adjacent diskettes or cooling fans.