A large amount of data in the data center is generated in various daily applications (such as some cloud applications, backup and archiving), which is not very high performance requirements for hard disk performance compared to data center business applications. The hard disk is required to have both large capacity and low cost. Therefore, we have seen that the hard disk manufacturers have not continued to develop higher-speed hard disks after the hard disk speed reaches 15k, but instead shifted the focus to improving the hard disk capacity. Recently, the 4TB large-capacity hard disk is already a mainstream market; and 5TB, 6TB or even Higher capacity hard drives are also gaining market share. On the other hand, in order to make the hard disk more suitable for cloud data centers and backup and archive applications, large-capacity hard drives will also be optimized for hard disk reliability and read/write control.
DVR is a video surveillance device that has gradually developed in recent years with the development of computer technology. In the security industry, tape-based long-delay video recorders are commonly used in traditional video surveillance projects. These video recorders use tape as a carrier for storing video data. Video data is stored in an analog manner. After repeated copying of the video signal, the signal attenuation is severe. Video tapes take up a lot of storage space, and maintenance and data retrieval are troublesome. With the development of computer technology, hardware and software technology updates provide new ideas for the storage of video data.
In order to ensure the normal operation of the car DVR, first ensure that the output power of the power board is stable. In a fixed narrow voltage environment, since the input voltage and current are basically stable, and in terms of electrical power, the output power determines the input power, so the power supply of the ordinary hard disk recorder only needs one adapter, and one adapter is nothing more than a transformer plus A filter circuit, a little conscience plus a protection circuit, no conscience protection circuit is not installed, cheap, so the average DVR cost and maintenance costs are relatively low. Secondly, from the perspective of seismic capacity, ordinary DVRs are not strict because of the fixed location environment, and the anti-seismic requirements of car DVRs are very important. The car is mainly based on low-frequency vibration, most cars are 20HZ. – 40HZ vibration is the main, the anti-shock treatment will cause the car DVR to crash, restart, the hard disk does not work, lost video segments and other issues.
Tape storage has an advantage over capacity, storage time, and price compared to disk storage. According to statistics, 80% of global digital information is stored on removable storage media, mainly tape, followed by disk. In the future, tapes are expected to continue to increase capacity faster than disks, thus opening up the price/performance difference with disks. After more than 50 years of continuous development and accumulation, tape technology has become mature and reliable, especially as users have more and more data to save for a long time, making tapes more advantageous than large disks in terms of large data storage.
In addition, the data stored on the tape can be stored for 30 years, while the hard disk is electronic. Make a hypothesis, if you save the data on the disk first, put it on for five years without power, wait until the time to power up, then you may not be able to read any data, because the electronic components are aging, so even if there are many Enterprises use low-cost NL-SAS/SATA disks as backup storage devices for data, but more enterprise users still need to use tape as a backup and historical data storage medium to achieve long-term data retention. Therefore, the greater space for tape storage technology lies in the storage of fixed content (so-called fixed content, which refers to data that does not change after writing), data archiving, and compliance applications.
The internal hard disk of the embedded DVR is integrated on one or two motherboards. After the technical integration of the manufacturer, the configuration is lower than that of the PC, and the performance of the operation can be high. The comparison between the machines is not inferior; from the software, the system is perfectly combined with the operating system of the DVR, which directly calls the hardware, speeds up the reaction time, improves the running speed, and reduces a lot of unnecessary. The extra features are running, and hard disk recorders based on Linux and Windows operating systems are absolutely impossible.
The use of SSD technology provides a flexible and efficient storage solution for surveillance systems that must be reliably and uninterrupted, withstand harsh environments and require minimal maintenance and service. High-capacity hard drives offer the highest cost efficiency and can store thousands of hours of video capacity without the need to rewrite or unload recorded content. The solid state can withstand harsh operating environments, such as shocks, vibrations, or high temperatures that are unavoidable in transportation environments such as cars, trains, subways, and ships.
The intelligent hard disk can receive commands sent by the host and efficiently manage the data in the solid state and hard disk storage components to reduce the resource requirements in the host. In order to protect data, such as solid-state components with errors or termination conditions, data will be transferred from the solid-state components to the hard disk. In the case of extreme temperatures and shocks, and outside the technical threshold of the hard disk, the content will be temporarily stored in the solid state component. In addition, critical recording data can be stored repeatedly on solid-state components and hard drives to ensure data recovery in the event of a system failure.
The key applications of OLTP and OLAP in the data center have very high performance requirements for storage. The main feature is a large number of random read/write IOs. Take the business transaction system as an example, not only will there be a large amount of business data input, but also There are a large number of random query requests. Simply put, to meet the needs of critical business, storage must have the advantages of high IOPS, low latency, and high bandwidth.
From the hard disk level, SSD is undoubtedly a high-performance representative. Because there is no seek delay, the current mainstream SSD IOPS can exceed two orders of magnitude of disk, and the performance of PCIe flash card can reach more than 200,000 IOPS. Performance, but because SSD still has a higher cost, if the amount of data is large, it needs 10k and 15k speed disks to complement the capacity.
Samsung CE hard drive is a more practical hard drive than ordinary PC hard drive. Ordinary hard disks will start at full speed when the power is turned on, and the instantaneous current may reach 2 amps or even higher. The Samsung CE hard drive will slowly accelerate when it starts up, and the startup current is controlled below 2 amps to support high-efficiency, low-cost power supplies. In addition, it has a real-time power saving function that allows any hard disk in the system to enter the power saving mode during non-operational periods. In this way, the system will be able to dissipate heat more effectively and greatly enhance the reliability of the overall system. Multiple hard disks are usually installed in the monitoring system. Even if a large starting current is generated at the moment of starting, the C E hard disk will not be burnt due to the unbearable power supply. At the same time, the average trouble-free running time of this series of hard disks is much longer than that of ordinary hard disks, and the stability and reliability are higher.
The digital hard disk recorder was originally used in the security monitoring fields such as finance and transportation. The image capture device such as the camera saves the required monitoring content in a specific format on the hard disk, so that any content can be selected for playback at any time. Since the storage medium is based on a hard disk rather than a conventional tape, we simply call it a “DVR.” Through configuration, digital DVR can easily realize data format conversion, encrypted storage, remote control, rate control and multi-channel simultaneous recording and playback. These are based on the characteristics of new technologies in the electronics and communication industry in recent years. It replaces traditional video recording methods based on traditional tape media. These new features, especially their high reliability and reusability, are equally tempting for the TV broadcast industry.
Another method of calculating health is to calculate the health based on the percentage of spare blocks in the SSD as a percentage of the total spare blocks in the SSD. The basis of this calculation theory is that when the flash memory is gradually worn out, the spare block is consumed to replace the bad block, and the more the spare block is consumed, the more the health display value is lowered. Some SSD vendors and some hard drive detection software use the remaining spare block method to display the percentage of health.
As the flash wear leveling algorithm becomes more and more robust, the health measured by the remaining spare block method cannot accurately predict the life expectancy of the solid state hard disk: the wear level of all flash memory cells is very close, and it is possible to generate a large number of bad blocks at the end of the burst. As a result, the spare block quickly falls, and the health is suddenly reduced from 100% to the end, which cannot be used as a reminder.