最近，RAID 技术(RAID technology)已在几乎所有应用中投入使用，例如台式机、服务器、笔记本电脑、存储设备以及需要大量硬盘驱动器的环境。RAID代表廉价磁盘冗余阵列。(Redundant Array of Inexpensive Disks.)它使用存储虚拟化技术来提高存储设备的性能和可靠性。
什么是 RAID？
RAID技术是一种将多个物理磁盘驱动器虚拟化为一个或多个称为RAID级别的逻辑单元的方法。每个文件的数据以称为RAID级别的多种方式分布在所有磁盘中。RAID级别的选择取决于磁盘驱动器的大小、所需的可靠性和性能级别。
磁盘配置为通过剥离分配负载将数据在磁盘之间划分，或者可以通过数据镜像进行配置，以确保可以恢复内容。还可以同时执行条带化和数据镜像，以获得这两个好处。早些时候只有五个RAID级别，如RAID 0、RAID 1、RAID 2、RAID 3 和 RAID 5(AND RAID 5)但是这些方案现在已经发展到适合广泛的应用程序。驱动程序配置为实现增强的数据保护、性能和容量。
RAID 实施
RAID技术可以实现为硬件RAID，其中设置是通过称为RAID控制器的特殊硬件将驱动器连接到主板来完成，或者它们也可以实现为软件RAID，其中设置是通过将驱动器直接连接到配置为的主板来完成然后由操作系统中的实用软件管理。RAID的类型 ，无论是最适合您的应用程序的专用硬件还是软件，都取决于您希望数据如何分布在多个驱动程序中。在本文中，我们比较了两种RAID实施，并帮助您为您的应用程序选择最佳RAID设置。
硬件 RAID
硬件 Raid(Hardware Raid)使用称为 RAID控制器的特殊硬件进行数据恢复和备份。.它的实现是基于RAID片上技术。它具有运行RAID(RAID)应用程序的处理器和高速缓存。
硬件 RAID 的好处
硬件 RAID(Hardware RAID)的主要优点之一 是它提高了系统性能。如前所述，硬件 RAID(Hardware RAID)有其专用的RAID处理器来运行RAID应用程序。所有复杂的配置都由专用处理器处理。因此，它通过在驱动器上分发内容和恢复备份数据的同时减轻主计算机处理器的压力，从而提高系统性能。
- 硬件 RAID(Hardware RAID)使用其DRAM高速缓存进行备份和恢复。这可以在写入数据备份时转化为更好的性能，同时减少恢复的停机时间。
- 硬件 RAID(Hardware RAID)添加了更多配置选项，例如混合配置，可更好地容忍一个或多个驱动器故障。
- 硬件 RAID在(Hardware RAID)RAID卡 上有内置的电池备份单元和板载闪存。这可以防止断电期间数据损坏。
- 硬件(Hardware)与不同的操作系统兼容，可以从任何系统访问。
硬件 RAID 的缺点
- 硬件 RAID(Hardware RAID)的成本更高，因为设置需要更多硬件。
- 硬件 RAID(Hardware RAID)不能为使用闪存(Flash)存储阵列 ( SSD ) 的某些设置提供更好的性能。
软件 RAID
与硬件 RAID 不同，RAID 软件(RAID Software)不使用任何特殊硬件来连接存储设备。这里存储设备直接连接到主机。跨驱动器的内容分发仅由主机(Host)操作系统中的实用软件管理。(Software)
软件 RAID 的好处
- 大多数主要操作系统，如Microsoft、Apple和 Linux都支持软件 RAID(Software RAID)配置。
- 与硬件 RAID(Hardware RAID)不同，软件RAID设置并不昂贵，因为您不需要任何专用硬件来设置RAID。RAID配置是在操作系统本身内完成的。
- 软件 RAID(Software RAID)主要适用于简单的RAID 0、1、10处理，不会对系统造成太大负载
软件 RAID 的缺点
- 软件 RAID在执行复杂的(Software RAID)RAID配置时会影响整体系统性能。如果驱动程序太多，则软件 RAID实施不合适。(Software RAID)
- 操作系统仅支持有限 的RAID级别，操作系统迁移的空间很小。
- RAID更容易受到病毒和其他安全攻击，因为它在主机系统内运行。
- 由于系统崩溃，服务器端问题会影响数据完整性。
软件 RAID(Software RAID)与硬件 RAID – 哪个(Hardware RAID – Which)更好？
最适合性能和数据可用性的RAID(RAID)类型因应用程序而异。软件RAID(Software RAID)主要适用于不会对系统造成太大负载的入门级RAID 0、1、10处理。(RAID 0,1,10)但是，它们不能用作高性能解决方案。
(Hardware RAID)应用程序主要使用硬件 RAID来扩展可用性和性能，而软件 RAID(Software RAID)主要适用于数据存储要求有限的工作站和不需要启动保护的入门级服务器。
话虽如此， Hardware RAID用于需要大量数据存储且性能卓越的工作站。由于硬件 RAID(Hardware RAID)使用专用控制器，因此更适用于需要复杂RAID配置且不会对软件 RAID(Software RAID)等系统资源施加过重负载的应用。
总之， 对于所有入门级服务器到企业级服务器来说，硬件 RAID是一个有吸引力的选择，可以提供最高的可用性和性能解决方案。(Hardware RAID)但是，如果您想在初始投资上节省一些钱，软件 RAID是一个有吸引力的选择。(Software RAID)
Software RAID vs Hardware RAID - Differences explained
In reсеnt time, RAID technology has been put into service in almost every application such as desktops, servers, laptops, storage devices and in environments which requires a large number of hard disk drives. RAID stands for Redundant Array of Inexpensive Disks. It uses storage virtualization technology to improve the performance and reliability of the storage devices.
What is RAID?
RAID technology is a way to virtualize multiple physical disk drives into one or more logical units called RAID levels. The data of each file is distributed among all the disks in several ways referred to as RAID levels. The selection of the RAID levels depends on the size of the disk drives, the required level of reliability and performance.
The disks are configured so that the data is divided among disks through stripping which distributes the load, or they can be configured through data mirroring which ensures the content can be recovered. It is also possible to carry out striping and data mirroring together to gain both benefits. Earlier there were only five RAID levels like RAID 0, RAID 1, RAID 2, RAID 3 AND RAID 5 however the schemes have now evolved to suit vast applications. The drivers are configured to achieve enhanced data protection, performance, and capacity.
RAID Implementation
RAID technology can be implemented either as a hardware RAID wherein the setup is done by connecting a drives to motherboard via special hardware called RAID controller or they can also be implemented as software RAID wherein the setup is done by connecting drives directly to motherboard whose configuration is then managed by the utility software in the operating system. The type of RAID, be it dedicated hardware or software that best suits your application depends on how you want your data to be distributed across multiple drivers. In this article, we compare the two RAID implementation and assist you in choosing the best RAID setup for your application.
Hardware RAID
Hardware Raid uses special hardware called RAID controller for data recovery and backup. .Its implementation is based on RAID on-chip technology. It has its processor and cache memory to run the RAID application.
Benefits of Hardware RAID
One of the major advantages of the Hardware RAID is that it boosts system performance. Like said earlier, Hardware RAID has its dedicated RAID processor to run the RAID application. All the complex configuration is processed by a dedicated processor. Thus it boosts system performance by putting less strain on the main computer processor while distributing contents on the drives and restoring the backup data.
- Hardware RAID uses its DRAM cache memory for backup and restoration. This translates to better performance while writing data backups and meanwhile has less downtime for restoration.
- Hardware RAID adds more configuration options like the hybrid configuration which provides better tolerance towards one or more drive failure.
- Hardware RAID has inbuilt battery backup units and onboard flash memory on RAID cards. This prevents data corruption during loss of power.
- Hardware is compatible with different operating systems and it can be accessed from any system.
Drawbacks of hardware RAID
- The cost of Hardware RAID is more because the setup requires more hardware.
- Hardware RAID doesn’t provide better performance for certain setups that use Flash storage arrays(SSD).
Software RAID
Unlike the Hardware RAID, the RAID Software doesn’t use any special hardware to connect the storage devices. Here the storage devices are directly connected to the host computer. The distribution of content across the drives is managed solely by the utility Software in the Host operating system.
Benefits of Software RAID
- Most of the major operating systems like Microsoft, Apple and Linux support Software RAID configuration.
- Unlike Hardware RAID, the software RAID setup is not expensive as you don’t need any dedicated hardware for the RAID setup. The RAID configuration is done within the operating system itself.
- Software RAID is mostly suitable for simple RAID 0,1,10 processing which doesn’t cause too much load on the system
Drawbacks of Software RAID
- Software RAID can affect the overall system performance while performing complex RAID configuration. Software RAID implementation is not suitable if there are too many drivers.
- Only limited RAID levels are supported by the operating system and there is little scope for operating system migration.
- RAID is more vulnerable to viruses and other security attacks as it is running inside the host computer system.
- The server-side problem can impact data integrity due to system crashes.
Software RAID vs Hardware RAID – Which is better?
The type of RAID that best suits the performance and data availability varies from application to application. Software RAID is mostly suitable for the entry-level RAID 0,1,10 processing which doesn’t cause too much load on the system. However, they cannot be used as a high-performance solution.
Hardware RAID is mostly used by the application to scale up the availability and performance whereas Software RAID is mostly suited for the workstation with limited data storage requirements and entry-level servers which do not require boot protection.
That being said, Hardware RAID is used in work stations that require large data storage and excel in the performance. Since the Hardware RAID uses a dedicated controller, it is more suitable for applications that require complex RAID configurations and don’t impose a heavy load on the system resources like the Software RAID.
In summary, Hardware RAID is an attractive option for all the entry-level servers to enterprise-level servers to have the highest availability and performance solution. However, Software RAID is an attractive option if you are trying to save some money on the initial investment.
