What is NAS?How to calculate?

NAS is short for network attached storage, which is called network attached storage in Chinese. In the NAS storage structure, the storage system is no longer attached to a specific server or client through the i/0 bus, but is directly connected to the network through the network interface, and accessed by users through the network.

Nas is actually a storage device with a thin server, similar to a dedicated file server. This dedicated storage server is different from the traditional general-purpose servers, it removed the original general-purpose servers do not apply to most of the computing functions, but only to provide file system functions for storage services, greatly reducing the cost of storage devices. This dedicated storage server is different from the traditional general-purpose servers, it removes the original general-purpose server does not apply to most of the computing functions, and only provides file system functions for storage services, greatly reducing the cost of storage equipment. In order to facilitate the storage to the network between the most efficient way to send data, specifically optimized system hardware and software architecture, multi-threaded, multi-tasking network operating system kernel is particularly suitable for dealing with i/o requests from the network, not only fast response speed, but also high data transfer rate.

Compared with the traditional server-centric storage system, data is no longer forwarded through the server memory (which causes additional delays and blocking), and is transmitted directly between the client and the storage device (the so-called third-party transmission), and the server only plays a role in controlling and managing the server, resulting in a faster response rate and higher data bandwidth. In addition, the lower requirements for the server can greatly reduce the cost of the server, which is conducive to the popularization of high-performance storage systems in a wider range of applications.

It has a better protocol independence, support for unix, netware, windows nt, os/2 or intranet web data access, the client does not require any special software, easy to install, and can even act as a network of other machines drive, you can easily use the existing management tools for management. With the traditional general-purpose server is different, nas dedicated server can not increase the complexity, management overhead, reduce reliability on the basis of the network storage capacity increases, with very good scalability (scalability). As the server does not need to provide more hardware and services, so that the reliability of the server and i/o performance greatly improved, can make full use of the available 10m ~ 100mb network bandwidth, there is a larger data throughput. nas can be easily accessed through the hub (hub) or switch tch) to the user network, is a plug-and-play network equipment. Provides users with easy to install, easy to use and manage, high reliability and scalability of network storage solutions. nas makes file access operations faster and it is easy to add file storage capacity to the infrastructure. Because nas focuses on file services rather than the actual file system implementation, nas appliances are often self-contained and fairly easy to deploy. The main thing that happens between a nas device and a client is the transfer of data. The large amount of data transferred over lan/wan today is divided into many smaller chunks of data. The processing of the transmission takes up processor resources to interrupt and re-access the data stream. Applications running on the same server are affected if the processing of packets takes too much processor resources. Since network congestion affects the performance of nas, one of its performance limitations is the ability of the network to transfer data. In addition, the scalability of nas storage is limited by the size of the device. It is very easy to add another device, but it is not easy to access the contents of a networked environment in the same way that you can access the data on a single machine, because nas devices usually have unique network identifiers. Because of these limitations, data backup in a nas environment is not centralized and is therefore limited to the use of direct-attached devices (such as dedicated tape drives or tape libraries) or to a network-based strategy where data on the device is backed up over an enterprise or dedicated lan. Unlike san, nas is a component-level approach to storage. nas connects storage devices to a group of computers via a standard network topology, so nas has a number of advantages in terms of applicability. First, nas can be connected directly to the Internet without a server and does not rely on a common operating system; instead, it uses a simplified user-oriented operating system designed specifically for data storage with the protocols needed to connect to the network built in, thus making the entire system easier to manage and set up. second, nas is a true plug-and-play product and is flexible in its physical location, allowing it to be placed in workgroups or in other locations to connect to the network. nas has not solved a key problem, is its bandwidth consumption in the backup process, the network bandwidth to meet both storage and normal data access. Now, a more consistent view is that nas can be a very economical solution to the problem of insufficient storage capacity, but it is difficult to obtain satisfactory performance for critical transaction applications, it must use a dedicated broadband network segment; therefore, if the company's growth will require a large number of nas devices or network bandwidth needs more than Gigabit Ethernet, you should consider the highest-end storage solution san. however, from the perspective of the applicability and tco perspective, nas should still be the preferred structure for most domestic enterprises. NAS Classification Electrical Server Electrical servers are the lowest-end product in the nas family of devices. Unlike the other storage solutions in this article, appliance-based servers are not specialized add-on storage devices. They provide a storage location for the network, but they are relatively inexpensive due to the lack of redundant as well as and high-performance components. If you're very focused on high reliability or top-notch performance (and you're willing to spend a bit more for it), you should still consider higher-end products in the nas category.

Features of nas:

1) low tco (total cost of ownership);

2) expandability;

3) cross-platform;

4) high availability;

5) high speed;

6) easy to install, maintain, and use.