In a video surveillance system, the choice of storage solution directly determines the system architecture of the entire system and the performance and stability of the system. Currently, there are two storage schemes in the video surveillance system. 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 storage device of the front-end DVR. In a better solution, the background software can manage and maintain multiple devices. DVR devices, including the storage data of these DVR devices, such as video transfer, delete and playback. All the data in this scheme 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 camera monitoring front end, and the storage is mainly stored in the background storage device by the PC or server software in the background.
The above two storage schemes have many drawbacks. Especially when there are many monitoring points and the amount of storage required is large, these possible disadvantages include: difficulty in maintenance due to storage fragmentation; storage due to low professionalism of storage The reliability is not high, which leads to the low reliability of the whole system; the utilization of storage is not high; the scalability of storage 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, 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 scenario, there are three levels:
1. Superior monitoring center: There is usually only one upper monitoring center, mainly composed of digital matrix, authentication server and VSTARClerk software.
2. Local monitoring center: There may be multiple local monitoring centers, which can be set according to geographic location or according to administrative affiliation. It is mainly composed of digital matrix, streaming media gateway, iSCSI storage device, VSTARRecorder software, etc. Mainly stored in the local monitoring center, this is the concept of distributed storage.
3, monitoring front-end: mainly composed of camera, network video server, which VE4000 series network video server can bring hard disk, the hard disk is mainly used for the network is not smooth, temporarily save the audio and video data, or need to save some in the front-end The case of 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 transceiver performance of the server, which affects the performance of the entire storage system, it is recommended to use a professional iSCSI storage device. IPSAN based on iSCSI technology
Introduction to iSCSI principle
This is a new Internet protocol based on storage network developed by the IETF. The principle is to transfer SCSI commands over an IP network, which makes it easier to transfer data over the network and enables remote storage management.
iSCSI enables standard SCSI commands to be transferred between a host system (initiator, IniTIator) and a storage device (target) on a TCP/IP network, and the iSCSI protocol supports the transfer of standard SCSI commands between systems. The connection between systems is achieved through a standard IP network infrastructure. The working principle of iSCSI is that when the end user or application (initiator) sends a request, the operating system will generate an appropriate SCSI command and data request. The SCSI command is encapsulated and performs encryption processing when encryption is required. These commands, combined with the header of the TCP/IP protocol, can be transmitted over Ethernet. The receiving end (target) unpacks in the opposite direction after receiving the packet, parses out the SCSI command and data request, and the SCSI command is sent 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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