server hard disk, as the name suggests, is the hard disk used on the server (Hard Disk). If the server is the core of network data, then the server hard disk is the core data warehouse, and all software and user data are stored here. For the user, the hard disk data stored on the server is the most valuable, so the reliability of the hard disk is very important. In order to make the hard disk adapt to the working environment of large data volume and long working time, the server generally adopts a high-speed, stable and secure SCSI hard disk.
Now the hard drive interfaces from points, can be divided into IDE hard disk and SCSI hard drives (there are still some support for PCMCIA interface, IEEE 1394 Interface, SATA interface, USB interface, and FC-AL (FibreChannel-Arbitrated Loop) Fibre Channel interface products, but relatively few); IDE hard drive is the hard drive we use every day, it is not cheap because of its low price, so it has been widely used on PC.
At present, most of the hard disks used on personal computers are hard disks of this type. Another type of hard disk is a SCSI hard disk (SCSI is a small computer system interface). Because of its good performance, such hard disk products are commonly used on servers, but at the same time it is expensive, so it is common. SCSI traces are not often seen on PCs.
Compared with ordinary PC hard drive, using the hard disk on the server has the following four characteristics.
. 1, the server uses
speed faster speed hard disk may be 7,200 or 10,000 revolutions per minute, or even higher; also arranged a large (typically 2MB or 4MB) of Write-back cache; average access time is short; external transfer rate and internal transfer rate are higher, using standard SCSI hard disk such as Ultra Wide SCSI, Ultra2 Wide SCSI, Ultra160 SCSI, Ultra320 SCSI, etc., the data transfer rate per second can be reached 40MB, 80MB, 160MB, 320MB.
2, high reliability
because the server hard disk is almost 24 hours non-stop operation, under tremendous workload. It can be said that if the hard disk has a problem, the consequences are unimaginable. Therefore, the current hard disk uses S.M.A.R.T technology (self-monitoring, analysis and reporting technology), and the hard disk manufacturers have adopted their own unique advanced technology to ensure data security. In order to avoid accidental losses, server hard drives can generally withstand 300G to 1000G impact.
3, multi-use SCSI interface
most servers use a large data throughput, CPU share of low SCSI hard disk. SCSI hard disks must be used through the SCSI interface. Some server motherboards integrate SCSI interfaces, some have dedicated SCSI interface cards, and one SCSI interface card can connect seven SCSI devices, which is unmatched by the IDE interface.
. 4, can be hot-swappable
hot-swap (Hot Swap) is supported by some of the server hard disk installation, in the case where the server can stop the machine, remove or insert a hard disk The operating system automatically recognizes changes to the hard disk. This technology is necessary for servers that run 24 hours a day.
Spindle speed
Spindle speed is the most important performance parameter in addition to capacity in all indicators of the hard disk. It is also the first to determine the internal transmission speed and continuous transmission speed of the hard disk. A decisive factor. Today's hard drives are typically 5400 rpm, 7200 rpm, 10,000 rpm and 15,000 rpm. From the current situation, the 10,000 rpm SCSI hard disk has the advantage of cost-effectiveness, which is the mainstream of the current hard disk, and the hard disk of 7200 rpm and below is gradually fading out of the hard disk market. //This article from the application of computer hardware and software network www.45it.com reproduced please specify
internal transfer rate
decisive factor is the evaluation of the level of the overall performance of a hard disk
internal transfer rate. The data transfer rate of the hard disk is divided into internal and external transfer rates; usually, the external transfer rate is also the burst data transfer rate (Burstdata Transfer Rate) or interface transfer rate, which refers to the speed of outputting data from the cache of the hard disk.
currently used external transfer rate Ultra 160 SCSI technology has reached 160MB /s; internal transfer rate, also known as maximum or minimum sustained transfer rate (Sustained Transfer Rate), refers to a hard disk to read and write data on the disc Speed, most of the current mainstream hard drives are between 30MB/s and 60MB/s. Since the internal transfer rate of the hard disk is smaller than the external transfer rate, only the internal transfer rate can be used as a true measure of the performance of the hard disk.