In a video surveillance system, what storage solution is selected directly determines the system architecture of the entire system as well as the performance and stability of the system. Currently, there are roughly two storage solutions in video surveillance systems. Video surveillance system storage solution
One is to use a DVR device with a certain storage capacity (such as 1.2T) in the camera monitoring front end. All the required data is stored in the front-end DVR storage device. In a better solution, the background software can manage and maintain multiple DVR equipment, including the storage data of these DVR equipment, such as the transfer, deletion, and playback of video functions. In this scheme, all data is mainly stored in the DVR, and the background is mainly responsible for maintenance and necessary storage.
The other is to use a DVR or network video server in the front end of the camera monitoring, and the storage is mainly stored at the remote end through the background PC or server software to save the data on the background storage device.
Both of the above storage solutions have many disadvantages, especially when there are many monitoring points and the required storage capacity is large. These possible disadvantages include: Difficult to maintain due to storage dispersion; due to low storage professionalism Reliability is not high, which leads to low reliability of the entire system; storage utilization rate is not high; storage scalability is not good.
In order to overcome these drawbacks, it is recommended to use IPSAN based on distributed storage, centralized management, and iSCSI technology as the storage solution for video surveillance. The main features of this solution include:
1. Distributed storage and centralized management;
2. IPSAN (STorageAreaNetwork) based on iSCSI technology;
3. The streaming media gateway can be used as the core device of the storage solution.
Distributed storage, centralized management
In this scheme, there are three levels:
1. Superior monitoring center: There is usually only one superior monitoring center, mainly composed of digital matrix, authentication server and VSTARClerk software.
2. Local monitoring center: There can be multiple local monitoring centers, which can be set according to geographical location or according to administrative affiliation, which is mainly composed of digital matrix, streaming media gateway, iSCSI storage equipment, VSTARRecorder software, etc .; audio and video data are all Mainly stored in the local monitoring center, this is the concept of distributed storage.
3. Surveillance front end: mainly composed of cameras and network video servers. Among them, the VE4000 series network video servers can be equipped with hard disks. The hard disks are mainly used for temporarily storing audio and video data when the network is poor, or need to save some Important data.
The storage device of the local monitoring center can also use a server with a SCSI disk array. However, due to the limited network sending and receiving performance of the server, which affects the performance of the entire storage system, it is recommended to choose a professional iSCSI storage device. IPSAN based on iSCSI technology
Introduction to iSCSI principles
This is a new Internet protocol based on a storage network developed by the IETF. Its principle is to transmit SCSI commands through an IP network, which makes it easier to transfer data on the network and achieve remote storage management.
iSCSI enables standard SCSI commands to be transferred between the host system (initiator, IniTIator) and storage device (target) on the TCP / IP network, and the iSCSI protocol supports the transfer of standard SCSI commands between systems. The connection between the systems is achieved through the standard IP network infrastructure. The working principle of iSCSI is that when an end user or application (initiator) sends a request, the operating system will generate an appropriate SCSI command and data request. , SCSI commands are encapsulated to perform encryption processing when encryption is required. These commands plus TCP / IP protocol headers can be transmitted over Ethernet. After receiving the data packet, the receiving end (target) unpacks it in the opposite direction, parses out the SCSI command and data request, and then sends the SCSI command to the SCSI storage device driver. Because iSCSI is a two-way protocol, it can Return the data to the original request.
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