May 24, 2021 That's what Linux should learn
Hard disk is one of the important components of computer hardware equipment, hard disk storage device reading and writing speed will also affect the overall performance of the server. Chapter 6, Chapter 7 explains the hard disk storage structure, RAID disk array technology and LVM technology are all technologies used for storage devices, although these technologies are at the software and hardware levels, but they are designed to solve the problem of hard disk storage device read and write speed, or strive to ensure the security of storage data.
In order to further improve the read and write speed and performance of hard disk storage devices, efforts have been made to improve the interface protocols of physical hard disk devices. The current hard disk interface types are IDE, SCSI and SATA.
IDE is a mature and stable, inexpensive parallel transport interface.
SATA is a faster and more complete serial transport interface for data validation.
SCSI is a common standard for system-level interface between computer and hard disk, optical drive and other equipment, which has the advantages of low system resource uutability, high speed and fast transmission speed.
No matter what type of hard disk interface is used, the data on the hard disk is always exchanged with CPU and memory devices through the bus on the computer board, which is a physical environment limitation that brings all kinds of inconvenience to the sharing of hard disk resources. L ater, IBM began developing new storage technologies based on the TCP/IP protocol and the SCSI interface protocol, the Internet Small Computer System Interface, which we can now see. T his is a new storage technology that combines SCSI interface with Ethernet technology and can be used to transmit commands and data of SCSI interface in a network. In this way, not only overcome the physical limitations of traditional SCSI interface devices, realize cross-regional storage resource sharing, but also expand storage capacity without downtime.
In order for readers to be aware of it and to be flexible in their use of the technology at work, here's an explanation of the advantages and disadvantages of iSCSI technology in a production environment. F irst of all, iSCSI storage technology is very convenient, in the form of access to storage resources has changed a lot, get rid of the limitations of the physical environment, but also can be divided into multiple servers to use, so it is a very recommended storage technology. H owever, iSCSI storage technology is constrained by network speed. I n the past, hard disk devices were transmitted directly from the bus on the motherboard, but now the Internet needs to be used as a carrier and channel for data transmission, so transmission rate and stability are bottlenecks in iSCSI technology. As network technology continues to evolve, iSCSI technology is expected to improve.
Since you want to transfer data on your hard drive device over Ethernet, is the data coming into your computer via a network card? T his makes it necessary to introduce the iSCSI-HBA card (see Figure 17-1). U nlike regular network cards (connecting network bus and memory for computer Internet access), iSCSI-HBA cards are connected to SCSI interfaces or FC (Fibre Channel) bus and memory, which are designed to exchange data between hosts and use protocols that are fundamentally different from normal network cards. Servers running Linux systems package hard disk device commands and data into standard TCP/IP packets based on the iSCSI protocol, which are then transmitted over Ethernet to the target storage device, and when the target storage device receives the packets, the TCP/IP packets are unziped into hard disk device commands and data based on the iSCSI protocol.
Figure 17-1 iSCSI-HBA card real picture