Design of Video Monitoring System for World Expo National Pavilion

In order to meet the needs of the Expo venues' safety and scientific and systematic management, to fully and timely understand and track any incidents that may 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 of video recording files adopts the method of hard disk recorders plugged into IPSAN. The storage time is about more than two weeks, and the total storage capacity requirement is about 100TB. The video storage structure is as follows:

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 of the solution:

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

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

3. The network storage solution is easy to use and economical, with a complete and independent configuration wizard interface, which makes system configuration simple and easy. It also helps reduce costs and complexity for surveillance storage environments with rapidly growing data.

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 IO, management and other aspects according to 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 invasion.

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 overall monitoring system. Therefore, dedicated storage for video data 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 the following four: hard disk, DAS, NAS, and SAN. These methods 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, 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, the expansion capability is extremely limited, and centralized data storage cannot be achieved.

In addition, the maintenance cost of the hard disk 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 for 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.

Direc (Direct Attached Storage) is a direct attached storage. It can easily expand the capacity of the platform by using DAS, and can provide multiple RAD levels of protection for data. Its connection method is shown in Figure 1:

DAS direct storage

Adopting DAS mode, deploy relevant HBA cards on the video storage unit. Used to establish data channels with the back-end storage devices. 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 mode 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 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). The full name is network attached storage, which is a professional network file storage and file backup device. At the same time, NAS can provide multiple RAID levels of protection for data. NAS devices and multiple video storage service units are connected through an IP network, communicate according to the TCP/IP protocol, and transmit data in the form of file I/O (input/output). A NAS unit includes a core processor, a file service management tool, and one or more hard disk drives for data storage.

The NAS method can support multiple hosts to read and write at the same time, and has excellent sharing performance and expansion capabilities. At the same time, NAS can be applied in complex network environments. The deployment is also very flexible.

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. SAN provides 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 the 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.