Server hard disk interface type
1. SATA interface
The SATA interface is also called "serial interface", so hard disks using the SATA interface are commonly called serial hard disks. It is an evolution after IDE hard disk. The physical design of SATA is based on Fiber Channel, so a four-core data cable is used. There are mainly three types of SATA interface specifications, among which the SATA-2 specification is commonly used at present, and the transmission speed can reach 3GB/s.
Because the server hard disk with SATA interface is quite mature in technology and the construction cost is not high, so compared with products of other interface types, its market price is relatively common. I believe that for enterprise users with low budget, it is the best choice to upgrade the SATA-2 interface hard disk with the same interface but larger capacity in the original server architecture.
2. SCSI interface
The server hard disk with SCSI interface is a kind used in most servers now. It has the characteristics of large data throughput and extremely low CPU occupancy rate: the SCSI controller used to connect the hard disk with SCSI interface has a control chip equivalent to the CPU function. , can replace the CPU to handle most of the work; now the Ultra 320 standard SCSI interface hard disk is widely used, and the data transfer rate can reach 320MB/s. The SCSI interface server hard disk and SCSI controller are shown in the figure.
In addition, SCSI hard drives have SCA2 interfaces that support hot-swap technology, and are also very suitable for deployment in current workgroup and departmental servers. SCSI hard disks can only be used through SCSI interfaces. Now server motherboards generally integrate SCSI interfaces, and special SCSI interface cards can also be installed to connect more SCSI devices, so their horizontal expansion capabilities are relatively strong.
3. SAS interface
"SAS" means Serial Attached SCSI. Simply understood, it refers to the upgrade and improvement of SCSI interface technology. The purpose is to further improve the performance, usability and expandability of SCSI technology. Its feature is that more disk devices can be connected at the same time, saving the internal space of the server; for example, the SAS interface reduces the size of the cable and is matched with a thinner cable.
Better space-occupying features make hard disks with this interface widely deployed in blade servers. Using eight 2.5-inch SAS hard drives within 2U height has become the choice of most OEM server manufacturers. In addition, for enterprises with low budget and unable to replace existing servers, the upgrade method of coexistence of SAS and SATA hard disks can also be adopted. The good backward compatibility of SAS interfaces allows enterprise users to use them in different applications. For example, SATA hard drives can be used for general transactional processing, while SAS hard drives can focus on applications with a large amount of data and extremely critical data availability.
Compared with Ultra 320 SCSI hard disks of the same capacity, SAS hard disks are more expensive, mainly due to their better scalability, compatibility and more reliable fault tolerance. From the perspective of the server market, major server manufacturers at home and abroad have launched models using SAS hard drives, but the application and market conditions of specific products are different.
4. Optical fiber interface
Fiber Channel (FC, Fiber Channel) is an interface developed to improve the speed and flexibility of multi-hard disk storage systems, which can greatly improve the communication speed of multi-hard disk systems. For large-scale ERP systems, or online real-time trading systems and other application environments that require greater transmission capacity and faster response speed, server hard disks with such interfaces are the best choice; of course, their product prices are naturally higher than the previous ones.
To sum up, server hard disks with different interface technologies also determine their respective better applicable environments. SATA hard disk server products that exist independently are rare nowadays, and most of them are tower servers for entry-level applications. SCSI and SAS have many characteristics such as low CPU usage and many connected devices, and their performance is obviously better than that of SATA interface hard drives. Therefore, they can be deployed in application environments such as enterprise data centers and security servers. At present, most of the server hard drives or server products on the market are in two forms: Ultra320 SCSI and SAS/SATA.