The server hard disk interface determines the technical structure and transmission performance of the product to a certain extent. Do you know what types of server hard disk interfaces are there? The server hard disk interface includes four types: SATA interface, SCSI interface, SAS interface, and fiber interface.
First, the scenery is still SATA interface
SATA interface is also known as the "serial interface", so the hard disk with the SATA interface is now called the serial hard disk. It is an evolution after the IDE hard drive. The physical design of SATA is based on Fibre Channel, so a four-core data cable is used. There are three main types of SATA interfaces to date. Among them, the SATA-2 specification is commonly used, and the transmission speed can reach 3GB/sec. As shown in Figure 1, the SATA-2 interface specifications adopted by a certain brand of SSDs are shown.
Now there is a SATA-3 interface, as shown in the figure is a SATA-3 interface server hard disk for Western Digital. In addition to increasing the transfer rate to 6GB/sec, the SATA-3 interface provides read optimization settings for many data types. Of course, for users, the emergence of SATA-3 interface does not mean that the existing SATA-2 products will be eliminated, because SATA-3 is compatible with the old SATA devices despite the new INCITS ATA8-ACS standard.
Due to the SATA interface server hard disk, the technology is quite mature and the construction cost is not high, so the market price is relatively popular compared to other interface type products. It is believed that for enterprise users with low budgets, upgrading the SATA-2 interface hard disk with the same interface but larger capacity in the original server architecture is the best choice.
Second, the application of more popular SCSI interface
The server hard disk of the SCSI interface is one of the types of servers currently used. It has the characteristics of large data throughput and extremely low CPU occupation. The SCSI controller for connecting the SCSI interface hard disk has a control chip equivalent to the CPU function. It can replace most of the CPU processing; nowadays, the Ultra 320 standard SCSI interface hard disk is widely used, and the data transmission rate can reach 320MB/sec. The SCSI interface server hard disk and SCSI controller are shown in the figure.
In addition, the SCA2 interface of the SCSI hard disk that supports hot plugging technology is also very suitable for deployment in current work groups and departmental servers. SCSI hard disks must be used through the SCSI interface. Now the server motherboards usually have integrated SCSI interfaces. You can also install a dedicated SCSI interface card to connect more SCSI devices, so the horizontal expansion capability is relatively strong.
So, what kind of server hard disk is the SCSI interface, which is better than what is applicable to the enterprise environment? First, SCSI has good support for redundant array of disks (RAID), which can meet the enterprise environment with big data storage. Data security is also guaranteed; in addition, the speed of SCSI hard drives has already reached 15,000 rpm, which ensures the processing performance of enterprise data centers is guaranteed; again, its low CPU usage and multi-tasking parallel processing features can grow. The enterprise environment provides strong data processing and storage support. Finally, from the current market price comparison shown in Figure 6, the SCSI interface hard disk is lower than the SAS interface hard disk as a whole, but significantly higher than the SATA interface hard disk, so it is more suitable for assembly with certain security for data storage. Enterprise environment with demand, capacity requirements, and high processing performance requirements.
Third, the pursuit of maximum performance SAS interface
"SAS" means serial connection SCSI. A simple understanding is the upgrade of SCSI interface technology. The purpose is to further improve the performance, availability and scalability of SCSI technology. Its characteristic is that it can connect more disk devices at the same time and save the internal space of the server; for example, the SAS interface reduces the cable size and is matched with a thinner cable, and the SAS hard disk has a 2.5-inch specification, as shown in Figure 7. It is the Seagate (Savvio 15K.2) 2.5-inch SAS hard disk interface.
The better space footprint makes the hard drive of this interface widely available in blade servers. Using eight 2.5-inch SAS drives in a 2U height has become the choice of most OEM server vendors. In addition, for enterprises that cannot afford to replace existing servers with low budgets, SAS and SATA hard disks can be used for upgrade coexistence. The backward compatibility of SAS interfaces allows enterprise users to use them in different applications. For example, SATA drives can be used for general transaction processing, while SAS drives can focus on applications where data volume is critical and data availability is critical. As shown in the figure, the ST-1042SAS-D7 hard disk extraction box introduced by S100 Information Technology (SNT) is a perfect hybrid to support the coexistence of SAS and SATA hard disks, and can be used with SAS or SATA hard disk control cards to support RAID 0, 1. 5 disk array mode.
Compared to the same capacity Ultra 320 SCSI hard drive, SAS drives are more expensive, mainly due to their better scalability, compatibility and more reliable fault tolerance. From the perspective of the server market, the main server manufacturers at home and abroad have already launched models using SAS hard drives, but the application and market conditions of specific products are different. For example, the HP ProLiant DL380 G5 targeted at departmental applications, the IBM System x3650 M2 for streaming services and e-commerce, all offer full support for SAS drives.
Fourth, the application of high-end fiber optic interface
Fibre Channel (FC) is an interface developed to improve the speed and flexibility of multi-disk storage systems, which can greatly improve the communication speed of multi-hard disk systems. For large ERP systems, or online real-time trading systems that require more throughput and faster response times, server hard drives of this type are the best choice; of course, the price of their products is naturally higher. In the first few.
To sum up, the server hard disks of different interface technologies also determine their respective better applicable environments. Separate SATA hard disk server products are rare today, mostly in tower servers for entry-level applications. SCSI and SAS have better performance than the SATA interface hard disk because of their low CPU usage and many connected devices. Therefore, they can be deployed in enterprise data centers and security servers. At present, it seems that most of the server hard disks or server products on the market are in two forms: Ultra320 SCSI and SAS/SATA.
It is undeniable that in 2009, SAS has become the mainstream hard disk platform in the server industry. In the near future, enterprise users with server hard disk upgrade requirements are still more inclined to choose the SAS platform, although the price is obviously higher than the one, but brought The actual application effect is better.