Advantages and disadvantages of four traditional storage methods

The problem of data storage is very important, but in practical application it is wrong. Often appear out of disk, Volume lock Deng Many problems, seriously affecting the overall system of normal use, so the data dedicated storage has become the market's most concerned about security products.

Traditional data storage mode

In the current digital world, the most common is the following four types of storage: hard disk, DAS, NAS, SAN.

1. Hard Drive

Whether the DVR, DVS after the hard disk or directly behind the server to connect the expansion cabinet, are the use of hard disk storage mode. It should be said that the use of hard disk storage, does not count as a strict storage system. There are several reasons for this:

First, it does not typically have a raid system and does not have redundant protection of the data on the hard disk, even if it is implemented via a host-side RAID card or soft raid. Seriously affect the overall performance;

Second, its expansion ability is extremely limited, when the video time exceeds 60 days, often cannot satisfy the video time storage demand;

Third, can not realize the data centralized storage, the later maintenance cost is high, especially after the DVS hangs the hard disk way, its maintenance cost often surpasses the acquisition cost in one year.

It should be said that the hard disk storage mode is not suitable for large-scale digital video surveillance system applications. In particular, the digital video surveillance system that requires long time video recording. Generally this approach is in the same system as other storage methods, as a buffer or emergency replacement for other storage methods.

2.DAS (direct attached storage)

Das (direct attached Storage), all referred to as directly attached to the storage, the DAS approach can be very simple to achieve capacity expansion of the platform, while the data can provide a variety of Rald level of protection.

When using Das mode. Deploy the associated HBA card on the video storage unit. Used to establish a data channel with the back-end storage device. The front-end video memory unit can be either DVR or video storage server. Its channel can use optical fiber, IP network cable, SAS cable and even USB, 1394 line and so on.

Das method can not support the simultaneous access of many video storage service units, and its capacity to enlarge depends heavily on the capacity of the storage device. Therefore, in the large digital video surveillance system, the application of DAS storage mode will cause the system maintenance difficulty greatly improved.

It is because of these features of DAS storage that this type of storage is typically used for DVR expansion or small digital video surveillance projects.

3.NAS (Network attached storage)

NAS (Network attached Storage). Known as network attached storage, it is a professional network file storage and file backup device, or network direct-linked storage device, network disk array. At the same time, NAS can provide multiple RAID level protection for data.

NAS devices and multiple video storage service units are connected through the IP network, communicating according to the TCP/IP protocol, and transmitting data in I/O (input/output) of the file. A NAS unit includes a core processor, a File Services management tool, and one or more hard drives for storing data.

Nas is a way to support multiple host-side simultaneous read and write, with excellent sharing performance and scalability, while NAS can be used in complex network environments. Deployment is also very flexible.

However, because NAS uses the CIF/NFS protocol for file-level transmission of data, the network overhead is very large, especially when the bandwidth used to write data is typically between 20%-40%. So the current NAS is generally used in small network digital video surveillance system or only for partial data sharing storage.

4.SAN (storage Area Network)

SAN (Storage area Network), called a storage Region network, is a high-speed private subnet that connects disk arrays to related servers via a connection device such as a switch. At the same time, San can provide multiple RAID level protection for data.

Sans provide a dedicated, highly reliable storage network. Allowing independent increases in their storage capacity also simplifies management and centralized control, especially when all storage devices are lumped together. Because of these characteristics, SAN architecture is especially suitable for storage applications of large network digital video surveillance system, which can deal with the storage of thousands and tens of thousands of front-end monitoring points.

The SAN is currently divided into Fc―san (Optical storage Area Network) and Ip―san (Ethernet storage Area network). The difference between them is the connection line and the use of the data Transfer Protocol. Although Fc―san because of the use of special protocol can ensure more stable and efficient transmission, but its deployment and construction costs are much higher than the Ip―san, so at present in the large network digital video surveillance system more use is Ip―san architecture.