In the next article, I will be more than the current IT's third wave - network storage. And use iSCSI this promising network storage mode as an instance, introducing the design and implementation of iSCSI.
Chapter 1 Why is there a network storage?
1.1 Economics of storage strategy
In 2002, the storage technology and products were more and more attention to the world. According to statistics, the demand for storage is increased by more than 100%. Global business activities have brought more online applications, the most obvious example is the development of Email, e-commerce, multimedia, document replication and data operations. In the last five years, all the data in the world rose by 1% by electronic storage to 10%, which is a significant change that accompanied by a lot of demand for storage. Information digitization means that the demand for storage will grow in geometric levels. The next 10% shift means unpredictable storage demand. The following table gives the growth of storage requirements:
Note: 1 petabyte = 250 byte
Why is the storage strategy so important? This mainly has the following reasons:
1. The annual investment in storage is significantly increased. The most important reason is that the demand for data storage is getting bigger and bigger, which is the biggest capital invested in storage.
2. Each company with security will protect their data at a lot of financial resources. Data not only plays an important role in general business activities, but also through the surface data, it is derived with value information, which can dig potential business opportunities to expand the development of the company.
The storage policy contains a lot of content: data access and retrieval, data security and consistency, performance requirements during data access, the scalability of storage space, compatibility, high investment return rate, etc.
1.2. Why need network storage
There are some shortcomings in traditional local storage: the management cost is high, the transmission distance is limited, and the scalability is limited. Especially when companies want to expand their storage capacity, they have to buy more servers. Moreover, the storage device must be placed near the server because the maximum length supported by the parallel cable connected to the SCSI device is only 12 meters. These restrictions drive the development of network storage.
