How Smart RAID Technology Be Used for NVR

Video surveillance has entered the era of network high-definition, large amounts of monitoring data is stored in the hard disk installation NVR(Network video recorder), IP-SAN, it is known, the current large-capacity hard disk is a precision mechanical parts, fault-prone itself, is a consumable item. Then the data stored directly on the hard disk to face the risk of data loss.

In traditional video surveillance applications, such as: residential, buildings, parks and other monitoring, data reliability is not high, the effective utilization of its monitoring data has been maintained at a very low proportion, if not lucky encounter hard disk failure loss of a hard drive data for these applications are affordable in terms of a large number of embedded video equipment manufacturers is the value of this, the introduction of single-disk mode inexpensive NVR, without having to support the cost of hard disk data redundancy brings promotion; not because the RAID, you can configure the same inexpensive monitoring level hard disk, greatly reducing the overall cost of video products and programs, low-cost advantages greatly enhance shipments of embedded NVR.

As we all know, RAID technology can eliminate the hard disk failure caused data loss and business interruption, but it also requests the hard disk itself, the general requirements of enterprise-class hard drive, this hard drive RAID firmware on various states in the work environment be adjusted distinctions, for example: the resonance can be generated when working with multiple hard drives for RAID to be well under head offset compensation, a hard disk error handling can be cured maximum response time, in order to avoid bug fixes for too long, is RAID hard disk is not mistaken It kicked response, better support concurrent read and write performance; these are greatly enhanced tuning enterprise-class hard drive availability RAID environments.

If the level is low-cost monitoring hard, because the drive firmware itself limits do not work well in RAID environments; for example: no correction for resonance disks, RAID environments increase the chances of data read and write errors, hard disk and monitor level no error handling and curing maximum response time, a busy hard drive error handling up to 2 to 5 minutes, and allow general RAID disk response time is about 30 seconds, causing RAID disk off phenomenon increases, even RAID initialization completed not; in RAID5 work and reconstruction process, before writing data to read large amounts of data to calculate the checksum, but monitoring level hard disk read performance is clearly not its write performance is good, a lot of reading IO queue often blocked, causing multiple disks increases the response time of severe, may lead to bulk out the disc.

For video surveillance applications, only afford to pay the high cost of enterprise-class hard drive high-end users can afford to enjoy the benefits of traditional RAID data reliability technology brings, traditional RAID-class hard drive and monitor poor performance has become compatible to a large number video surveillance in low-end users universal resistance.

Therefore, the video surveillance applications for traditional RAID asked the following challenges:

1, requires a low-cost non-configurable enterprise-class hard drives set up RAID group, reducing the cost of hard disks;

2, required to reduce the large capacity hard disk rebuild times, improve reconstructed power;

3, demands for improvement in the availability of non-enterprise-class hard disk RAID group;

See more demand, Sysvideo traditional RAID algorithms for rehabilitation and upgrading, development of a new generation of Smart RAID technology, which idea is to reduce the minimum hard disk management unit, to narrow the fault locally, so as to enhance the overall availability of hard disk RAID group; while optimizing the RAID level to monitor the response time of a hard disk failure tolerance, which greatly enhance the non-enterprise-class hard drives (including monitoring level hard disk) is RAID availability.

In Smart RAID formation process, the first hard disk fragmentation process, each physical disk will be broken into 64 parts, small data blocks at the same position of each physical disk will be organized as a basic unit of Smart RAID management, more a Smart RAID management unit may form one large logical volume of external use; Smart RAID level RAID management unit includes all the attributes, such as media detection, fault kick plate, hot standby replacement, reconstruction, etc; under actual operating conditions, when the physical track sectors of a hard disk failure, to block out the disk failure, replace the hot spare, the rebuild operation can be completed within a group Smart RAID, greatly reducing the amount of reconstruction IO read and write, and to shorten the overall time to complete the reconstruction of ; the last four blocks of each physical disk is used as a hot spare. As shown below:

On the issue of video surveillance in RAID technology and applications development
The benefits of using RAID technology after Smart obvious, because of the response time monitor the level of fault tolerance hard disk upgrade, make use of hard disk RAID5 group level to monitor the availability of improved significantly, frequently swap disk phenomenon has been effectively resolved.

In actual operation, the performance of the hard disk failure occurred in operation of 90% are concentrated in the local errors caused by abnormal reading and writing, because the circuit or mechanical malfunction causes the entire disk does not work it is rare, so when the hard disk error occurs, Smart RAID technology can play a good advantage partial reconstruction, reconstruction completed just 10 minutes; even the entire disk failure occurs, Smart RAID can be the same as for traditional RAID physical disk block kick plate, Reconstruction.

Moreover, if two simultaneous physical hard disk sector error, the traditional RAID5 group encountered such a situation will collapse, all the data is not available, but Smart RAID technology can be a very good these faults independence, divide and rule, data is not affected.

From the point of view, Smart RAID NVR technology is indeed better able to meet the demand for video surveillance applications RAID data redundancy, significantly enhance the capacity of non-availability of enterprise-class hard drive RAID.