What's server hard disk
for user data stored on the server's hard disk is the most precious, so it is very important to the reliability of the hard disk.In order to make the hard disk can adapt to large amount of data and long working hours and working environment, server usually use high speed, stability and safety of SCSI hard drives.Now the hard drive from the interface, can be divided into the IDE hard disk and SCSI hard drives (there are still some supported PCMCIA interface, IEEE 1394 interface, SATA interface, USB interface, and FC - AL (FibreChannel - Arbitrated Loop) fibre channel interface products, but relatively very little);IDE hard disk or hard disk, we use in our everyday it due to the low price and performance is not poor, therefore, has been widely used in the PC, the PCS for this type of hard disk drives most are.Another type of hard disk is the SCSI hard drives (SCSI or Small Computer System Interface Small Computer System Interface), due to its good performance, so on the server is using such hard disk products generally, but at the same time, its price is expensive, so on ordinary PC don't often see SCSI.The characteristics of the
server hard disk
server USES the hard disk rotational speed is fast, can achieve 7200 or 10000 revolutions per minute, or even higher;It also configured with a large (generally is 2 MB and 4 MB) back to the write cache;The average access time is shorter;External transfer rate and internal transfer rate is higher, the use of Ultra Wide SCSI, Ultra2 Wide SCSI, Ultra160 SCSI, Ultra320 SCSI standard SCSI hard drives, data transfer rate respectively can reach 40 MB per second, 80 MB, 160 MB, 320 MB.Because the server hard disk is almost
2, high reliability,
working around the clock, under a lot of effort.Hard disk, as it were, if wrong, the consequence is unimaginable.So now, the hard disk S.M.A.R.T technology is adopted, the monitoring, analysis and reporting technology), at the same time hard disk vendors have adopted the advanced technology of their own to ensure data security.In order to avoid the unexpected costs, server hard disk are generally able to withstand the impact of the 300 g to 1000 g.More than
3, use the SCSI interface
most server adopted large data throughput, low CPU occupancy SCSI hard drives.SCSI hard drives must be through the SCSI interface to use, and some SCSI interface is integrated in the server motherboard, some with a dedicated SCSI interface card, a SCSI interface card can pick seven SCSI device, this is can't be matched by the IDE interface.
hotplug can support Hot plug (Hot Swap) are supported by the server hard disk installation, can be on the server without downtime, pull out or insert a disk, changes in the operating system automatically recognize the hard disk.The technology for 24 hours non-stop operation of the server, it is quite necessary.
when comparing a server hard disk performance, should see the following main indicators:
spindle speed is a all the indicators of the hard drive in addition to capacity, should the most eye-catching performance parameters, and decided to drive the internal transmission speed and continuous transmission speed of the first decision factors.Now more than hard disk rotational speed is 5400 RPM, 7200 RPM, 10000 RPM and 15000 RPM.From the point of the current situation, 10000 RPM SCSI hard disk with the advantages of high cost performance, is the mainstream of the current hard disk and below 7200 RPM and its level of hard disk in the market gradually fade out the hard disk.The discretion of the
internal transfer rate
internal transfer rate is the decisive factors in the overall performance evaluation of a hard disk.Hard disk data transfer rate can be divided into internal and external transfer rate;Often refer to external transmission Rate for data Transfer Rate (Burstdata Transfer Rate) or interface Transfer Rate, refers to the outward from the hard disk cache the output data, the speed of the current using Ultra 160 SCSI external transmission Rate has reached 160 MB/s;Internal Transfer Rate also known as the maximum or minimum continuous Transfer Rate (Sustained Transfer Rate), refers to the speed of the hard disk read and write data on the disc, now most of the mainstream of the hard disk in 30 MB/s between 60 MB/s.As a result of the hard drive internal transfer rate than the external transfer rate, so only the internal transfer rate can be as the true measure of hard disk performance.
single disk capacity
except for the contribution of capacity growth, another important significance of the single disk capacity is hard disk data transmission speed.Single disk capacity increase due to the increase of the track number and track the linear magnetic density increases.The increase of the track number is of great benefit to reduce head seek time, because the radius of the disk is fixed, the increase of the track number means that the track of shortening the distance between, and head to move from one track to another track in place of time will be shorten as needed.This will help improve the quality of random data transmission speed.While the growth of linear magnetic density in the track and persistent hard disk data transmission speed has a direct link.Track in the increase of linear density can store more data in each track, and in each circle disc more data is read from the head to the hard disk in the buffer.
average seek time
average seek time refers to the head movement to track the time required for data is, this is the important indicators of hard disk mechanical properties, generally between 3 ~ 13 ms ms, suggested that the average seek time is greater than 8 ms don't consider the SCSI hard drives.The average seek time and the average latency time (completely determined by the speed) determines the hard disk heads together to find data in the cluster.This time a direct impact on the hard disk random data transmission speed.
to improve the capacity of hard disk cache is a short cut to improve overall performance of hard disk.Because of the hard drive internal data transmission speed and external transmission speed is different.So you need to cache for a speed adapter.The size of the cache to disk continuous data transmission speed has a great impact.It has a capacity of 512 KB, 2 MB and 4 MB, 16 MB, 8 MB or even for video capture, video editing job that requires a large amount of disk input/output, large hard disk cache is the ideal choice.