Surveillance Solution for the Storage of Digitalized Traffic

The third generation digitalized monitoring system, with large data volume and many management servers, belongs to centralized save mode, needing professional memory system to succeed in video saving.
Accompanying city economy fast development, vehicles amount rises greatly. Although basic road facilities have become much better than before, traffic jam problem is still hardness.
In order to make the situation better, all cities have been carrying out the plan of real-time monitoring on important crossroads, i.e. there install a set of intelligent monitoring system on spot, then video will be transmitted to control center for manager to manage monitoring equipments or cope events, thus road traffic is well organized. In this system, no matter run a red light or reversal drive, the vehicles will be captured and recorded by license plate number recognition camera or other monitoring device, even illegal information is printed at traffic management center instantly. The application of high tech enhances operation efficiency and eases drivers as well.
Demand analysis
By far, there are three kinds of solutions for traffic surveillance: based on traditional analog monitoring mode; based on DVR digitalization monitoring mode; based on DVS remote monitoring mode.
The first mode refers to traditional analog monitoring, adopting cassette save and facing to be eliminated.
The second mode mainly bases DVR. DVR is placed beside camera but connected, then converts & compresses signal and save them at the local, moreover, transmits the signal to control center through network. Since road monitoring point is not a lot, DVR can save signal by itself, besides, important data can be transmitted to professional memory device through network. DVR can be placed at sub-control room connected to camera with optical fiber. At that time, sub-control center may receive numerous video channels with large data volume, so it is feasible to add HDD unit for storing more.
The third generation digitalized monitoring mode is our talked main part, especially the video record and image saves. It includes three parts: front-end section of traffic surveillance, network & port devices and control center.
The front-end includes camera, pan/tilt, housing, wiper, bracket and DVS (sometimes DVS places at control center). Above all, DVS is the core of front-end equipments, connects to camera by BNC port, to decoder or alarm detector by RS232, to network port device by RJ45 port. DVS is used to collect spot situation of road, upload them to control center after compression & decode.
As to transmission, it is operable to adopt fitted routers according to bandwidth demand, network condition and economical efficiency.
As the "commander" of whole system, control center connects to all front-end equipments by network so as to achieve real-time display, control, save and management function. Control center’s hardware is mainly composed by DVR, monitor, memory device and printing devices.
Solution
Generally speaking, due to scattered & numerous monitoring points, the data of needing saved includes monitoring video, traffic violation picture and management signal from control center. According to the configuration of hardware, save management server of control center can receive as many as 100~150 video streams, so control center should set up multiple save management servers. In light of DAS (direct attached storage) weakness of low capacity utilization and of low expansion ability, we suggest adopt SAN framework. The details shows in topology diagram.
Solution feature
This solution with professional memory system overcomes the hardness of heavy storage of traffic surveillance, of video & picture security and of system volume expansion, as well as defines storage space according to different data security level in order to save spaces.
Large volume storage, easy expansion
If there only adopt DVR and server to save video, it can provide no more than 10TB volume. Especially when HDD amount inside DVR and server overpasses a number, whole equipment will become unstable due to cooling problem.
Adopting professional save equipment DC-4000 RAID, single device can provide up to 50TB volume and whole SAN system can provide hundreds of TB volume.
Realize safe storage
Professional memory device can provide safer protection for video recording, e.g. RAID 6 can avoid losing data and ensure system works normally when 2 HDD are broken. Roaming function makes HDD pulled out from broken device to other similar device with intact data. Besides, special cooling designment keeps system working normally in various conditions.
Choose high intelligent equipment
What is the "Roaming"? Simply speaking, if we have 2TB data stored in 5*500GB RAID and if device breaks down, we can pull out the 5 HDDs and push into any other similar device with same effect. Such a function greatly protects user’s data safety, suitable for the users who adopt single brand devices.
The virtual volume skill is originally used in high rank memory devices. But because of the usability and the flexibility meeting more memory modes, it has been applying in more and more middle & low rank products also. If user has 3 kinds of or more data with deferent protection grades, sizes and transmission speeds, it is necessary to adopt virtual volume RAID rather than common RAID.