iSCSI Technology and Applications

The need to establish an industry-standard transmission of stored information over an IP network exists simultaneously, but The question is how to establish this standard and make it a unified standard for the industry.

Bechtolsheim and his team formed a partnership with IBM to draft a standard for the new protocol called iSCSI (Internet SCSI), which allows SCSI commands to be transmitted over the TCP/IP protocol. In February 2000, the group submitted the draft as an Internet standard draft to the Internet Engineering Task Force (IETF). In March of the same year, the IETF meeting discussed the draft and decided to set up an IETF working group to develop technology for storing information via IP transmission. As of August 2000, the number of members of the IETF team has increased to 500, representing 200 companies or organizations, including almost all storage, network components and system vendors.

Currently, about iSCSI standard-setting has entered the final stage, it is estimated will be launched early next standard. The IETF has announced that it has completed the work of the iSCSI protocol and will now assign a comment number to it. This specification specifies how software handles SCSI packets on the intranet and how to process SCSI packets over long distances and how to encapsulate them in TCP/IP commands.

Comparison of iSCSI and FC (Fibre Channel)

Network storage is mainly composed of three parts: server (host), exchange (switch) and storage device (target). Among these three, exchange is very important. There are two ways to exchange network storage, one is Fibre Channel (FC) and the other is iSCSI.

from the point of view of data transmission, fiber channel and iSCSI are very different: a transmission which employs Fiber Channel FCP protocol, iSCSI uses the existing TCP protocol on the Internet. The FCP protocol was originally designed in accordance with the advanced protocol of the Fibre Channel network, and it works closely with low-level network functions. iSCSI is developed with the existing protected transport mechanism provided by TCP. Therefore, due to the different mechanisms, it is impossible to be compatible between iSCSI and Fibre Channel.

compared with Fiber Channel, iSCSI has its many advantages, mainly in the iSCSI more economical. Cost savings can be reflected in the following aspects: (1) Public technology existing between general data and SAN networks can reduce training costs, and there is no need to set up separate staff members, both of which can reduce costs. And a large number of Ethernet installation bases can also reduce the price. (2) iSCSI can leverage the existing, easy-to-understand TCP/IP infrastructure to build a SAN. As QoS and security advances, sharing between storage and existing infrastructure indicates hardware, training Several aspects, such as implementation, have the opportunity to achieve considerable cost savings. (3) With the implementation of Gigabit Ethernet, users will get a storage network with a transmission rate of 1 Gbps without changing the existing infrastructure.

FC (Fibre Channel) installed base little understanding of its technology, not many people, but it is very expensive. FC offers slightly better performance at the same speed, but this does not compensate for the high cost of the high cost and additional training costs required to achieve it. Recently, FC has temporarily maintained its dominance in SAN technology before Ethernet speeds exceed FC, but this is limited to a period of time before iSCSI became a climate.

However, iSCSI within three to five years will not replace Fibre Channel. First of all, although the TCP/IP network has many merits, its fatal problem in transmitting data blocks has not yet made a breakthrough in technology. Although Fibre Channel needs further improvement and improvement in terms of standards, long-distance connectivity, cost, etc., it has achieved remarkable results in the regional SAN field. Its products and technologies are gradually maturing. So, for now, Fibre Channel is the only option if users need high-capacity, high-speed block-level data access. However, as iSCSI matures, it will share the storage market for Fibre Channel. In addition, the efforts of vendors such as Brocade, Intel, and Cisco will also promote the convergence of Fibre Channel and iSCSI technologies, complement each other and develop together
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Advantages and Limitations of iSCSI

Advantages of iSCSI Technology: The foundation of iSCSI is traditional Ethernet and Internet. In the past 20 years, network technology The rapid development has made traditional networks ubiquitous, and iSCSI has a good foundation and can greatly reduce the total cost of ownership.

With the advancement of technology, the bandwidth of IP networks has developed rapidly. 1Gbps Ethernet has already occupied a large number of markets, and 10Gbps Ethernet is ready to go. Moreover, the agreement is supported by industry giants including IBM, Cisco, Intel, Brocade, and Adaptec. At the same time, a number of new vendors are also competing, such as Nishan System, SAN Valley, CNT, Pirus, and 3Ware.
In terms of technology implementation, iSCSI has a strong and effective IP and Ethernet architecture as the backbone, which greatly increases the tolerance. In addition, simple management and deployment is also a reason why iSCSI is the heart of the industry, because traditional network vendors have trained a lot of professional network talents, and can easily have professional iSCSI talents without training.

iSCSI is a technical standard based on the IP protocol. It implements the connection between SCSI and TCP/IP protocols. For users with LAN as the network environment, it requires only a small investment and can be conveniently and quickly Information and data are transmitted and managed interactively.

completely solve the remote data replication (Data Replication) and disaster recovery (Disaster Recover) problems. In terms of security, the past FC-SAN and DAS are mostly in a regulated environment with relatively low security requirements. iSCSI reverses this concept and circulates stored data within the Internet, making users feel the need to improve security. Therefore, iSCSI has built-in support for IPSEL mechanisms and enforces instructions at the chip level to ensure security.

However, when talk about iSCSI storage engineers prospects, but also need to analyze the current situation and development direction of seeking truth from facts. In fact, so far, there is not a mature product to show the charm of iSCSI, it has not been widely commercialized. And the problems faced by storage networks, iSCSI can not be solved, such as the contradiction between distance and bandwidth. Although iSCSI satisfies the need for long-distance connectivity and facilitates the connection of wide-area storage, the bandwidth of IP is still an unsolvable problem. Although IP networks are growing rapidly and 1Gbps networks are gaining popularity, bandwidth is still quite expensive from the WAN. Even with iGbps data transfer with 1Gbps bandwidth, the speed is not ideal. Moreover, the efficiency and latency of IP networks are a huge barrier to storing data transmission.