Brief Analysis of Video Surveillance Recording Storage Technology in the China National Pavilion at the World Expo

Introduction to the China Pavilion at the World Expo

The architectural appearance of the China Pavilion at the Shanghai World Expo is based on the concept of "Crown of the East", expressing the spirit and temperament of Chinese culture. The National Pavilion rises in the center and is stacked and protruding, becoming a sculptural shape that condenses Chinese elements and symbolizes the Chinese spirit - the Crown of the East; the regional pavilions are spread out horizontally, with the form of a stretched platform base against the National Pavilion, becoming an open, flexible, people-friendly, and layered urban square; the two complement each other and form a unified whole that expresses the theme of a great country in a prosperous era. The National Pavilion and the Regional Pavilion are divided into upper and lower functional areas, and the shapes are coordinated with the main and subordinate ones. The space is dominated by the north-south main axis, forming a spectacular urban space sequence and a unique landmark building group. Considering the structure and unique shape of the National Pavilion, the establishment of a video surveillance system can effectively guarantee the daily operation of the venue, and its system construction is also very challenging.

Features of the video surveillance system of the China Pavilion at the World Expo

In order to meet the needs of the safety and scientific and systematic management of the Expo venues, to fully and timely understand and track events that occur at any time, to quickly make correct judgments and responses to unexpected situations, and to give correct and rapid commands and processing, the number of cameras used in the front-end equipment of the monitoring system of the entire venue exceeds 300 channels of high-definition, and the storage and preservation method of video recording files adopts the method of hard disk recorder external IPSAN. The storage time is about more than two weeks, and the total storage capacity requirement is about 100TB. Its structure is shown in "Figure 1 Video Storage Structure Diagram".

This video surveillance storage device provides video surveillance video storage space to all video encoding devices, including video servers (NVS) and network hard disk recorders through IP networks. Other servers or monitoring devices can read video surveillance videos directly from the disk array or read video surveillance videos through video encoding devices.

Advantages

(1) Make full use of network advantages, flexibly deploy storage devices, and restrict and protect the access of authorized users to stored video data, which is conducive to external defense and internal control.

(2) Flexible data access and seamless support for the comprehensive application platform of video surveillance data are beneficial to the expansion of monitoring system functions.

(3) Network storage solutions are easy to use, economical, and have a complete and independent configuration wizard interface, which makes system configuration simple and easy. For those surveillance storage environments with rapidly growing data, it also helps reduce costs and complexity.

(4) Large capacity and low cost. One storage system can store 300 channels of video recordings for up to 30 days. Whether in terms of storage performance, capacity, reliability or availability, it can well meet the video surveillance storage needs of key areas.

(5) Compatible with various video encoding devices and supports video encoding devices from most mainstream video surveillance equipment manufacturers, including NVS, DVR and PC-DVR.

(6) Professional and reliable storage devices are optimized in terms of IO and management based on the characteristics of video surveillance storage. It supports multiple Raid level settings such as Raid 0/1/5/6/10/50, network redundancy, power supply, fan and other hardware redundancy, network fault recovery and system image backup, and other technical means to enhance data security and reliability, and has excellent defense capabilities against virus attacks.

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Video surveillance video data storage technology

The security industry has made great progress in China, with major projects such as "Safe City", "3111 Project" and "Global Eye" being launched; video surveillance is widely used in transportation, food, customs, energy, finance, national defense and other fields, and the market prospects are quite promising. As an important part of network digital video, the storage system often encounters many problems such as disk drop and volume lock in actual application, which seriously affects the normal use of the monitoring system as a whole. Therefore, dedicated video data storage has become one of the most concerned security products in the market. In the current digital video field, the most commonly used storage methods are hard disk, DAS, NAS and SAN, and they all have their own shortcomings.

harddisk

The method of mounting a hard disk behind a DVR or DVS or directly connecting an expansion cabinet to the back of a server is to use a hard disk for storage. It should be said that storage using a hard disk cannot be considered a storage system in the strict sense. The reasons include the following:

First of all, hard disks generally do not have RAID systems, and there is no redundant protection for the data on the hard disk. Even if there is, it is implemented through a host-side RAID card or soft RAID, which seriously affects the overall performance.

Secondly, its scalability is extremely limited and cannot achieve centralized data storage.

In addition, the cost of hard disk maintenance is high, especially when the hard disk is mounted behind the DVS. The maintenance cost often exceeds the purchase cost within one year. It should be said that the hard disk storage method is not suitable for the application of large-scale digital video surveillance systems, especially digital video surveillance systems that require long-term recording. Generally, this method coexists with other storage methods in the same system as a buffer or emergency substitute for other storage methods.

DAS direct storage

DAS (Direct Attached Storage) is the full name of direct attached storage. Using DAS can easily expand the capacity of the platform and provide multiple RAID levels of protection for data.

Using the DAS method, relevant HBA cards are deployed on the video storage unit to establish a data channel with the back-end storage device. The front-end video storage unit can be a DVR or a video storage server. Its channel can use optical fiber, IP network cable, SAS cable or even USB. The DAS method cannot support the simultaneous access of many video storage service units, and its expansion capacity is heavily dependent on the expansion capacity of the selected storage device itself. Therefore, in large-scale digital video surveillance systems, the application of DAS storage will greatly increase the difficulty coefficient of system maintenance. It is precisely because of these characteristics of DAS storage that this storage method is generally used for DVR expansion or small digital video surveillance projects.

NAS Network Attached Storage

NAS (Network Attached Storage), full name is network attached storage, is a professional network file storage and file backup device, and NAS can provide multiple RAID levels of data protection. NAS devices and multiple video storage service units are connected through IP networks, communicate according to TCP/IP protocol, and transmit data in the form of file I/O (input/output). A NAS unit includes a core processor, file service management tools, and one or more hard disk drives for data storage.

The NAS method can support simultaneous reading and writing by multiple hosts, and has excellent sharing performance and expansion capabilities. At the same time, NAS can be applied in complex network environments and is very flexible to deploy.

However, since NAS uses CIF/NFS protocol for file-level data transmission, the network overhead is very large, especially when writing data, the bandwidth utilization is generally only 20%. Therefore, NAS is currently generally used in small network digital video surveillance systems or only for shared storage of part of the data.

SAN Storage Area Network

SAN (Storage Area Network), the full name is storage area network, which is a high-speed dedicated subnet that connects disk arrays to related servers through switches and other connecting devices. At the same time, SAN can provide multiple RAID levels of protection for data and provide a dedicated, highly reliable storage network. It allows their storage capacity to be increased independently, and also makes management and centralized control simpler. It is precisely because of these characteristics that the SAN architecture is particularly suitable for storage applications in large-scale network digital video surveillance systems and can handle the storage of thousands or tens of thousands of front-end monitoring points. At present, SAN is mainly divided into FC-SAN (Fiber Storage Area Network) and IP-SAN (Ethernet Storage Area Network). The difference between them is the connection line and the different data transmission protocols used. Although FC-SAN uses a dedicated protocol to ensure more stable and efficient transmission, its deployment method and construction cost are much higher than IP-SAN, so IP-SAN architecture is currently more commonly used in large-scale network digital video surveillance systems.

The Expo National Pavilion adopts a SAN storage architecture for IP networks, which is fully compatible with direct video input from front-end network digital products. Aiming at the special industry model of video surveillance, optimization is carried out at the system platform level, and the front-end digital encoding equipment directly writes the digitized video data into the IP-SAN equipment. The system architecture is fully utilized to effectively reduce the number of devices, reduce the management difficulty, maintenance intensity, and energy consumption of the overall system.

Conclusion

The security monitoring systems at home and abroad have developed substantially after the "9/11" attacks in the United States. Various security companies are constantly innovating technologies and developing products. Through the test of actual monitoring needs such as the Olympic Games and the World Expo, the security monitoring systems of future venues will integrate more advanced technologies to continuously strengthen the safety of personnel and provide important guarantees for social harmony.