Software or hardware RAID - what's the difference?
When you deal with the topic of RAID, sooner or later you will notice differences between software and hardware RAIDs. Ultimately, both do the same thing: they connect multiple hard drives to a RAID volume. Nevertheless, there are a few advantages and disadvantages.
Software RAID - the simple and inexpensive variant
A software RAID is a RAID system that uses the computer's main processor for all of its calculations. It can be implemented at various levels: at the BIOS level, you can already use a software RAID to install your operating system on it. These so-called HostRAID systems are installed in the same way in many mainboards and only have to be set via the BIOS. Nevertheless, you do not have your own controller, so you also use the CPU. You can also run software RAID at the operating system level.
- Under Windows you can, for example, combine several hard disks into a RAID in the disk management. In the Home Premium version of Windows 7, only one RAID 0 is available, i.e. a combination of several disks to form a large volume. Windows 7 Professional offers you more: here you can also set up redundant volumes.
- Linux offers you a good range of functions. With "Linux Software RAID" or MDRAID you can set up almost everything from RAID 0 to 10.
- In OS X, you can use the hard disk utility for internal hard drives to set up RAID 1 or 2.
Advantages and disadvantages of software RAIDs
- Plus: Software RAIDs are often available as open source software or are included with the operating system. You can get a RAID cheaply if you don't want to spend on a RAID card or NAS. Your computer is sufficient and you can set up a RAID 1 (mirror) from two hard drives.
- Plus: If the installation of your operating system breaks down, you can often read the RAID again with a new installation of the same operating system. This is not always the case with host RAID systems.
- Minus: Software RAIDs use the processor and thus consume resources, the computer can become noticeably slower in complex systems.
- Minus: With a RAID that you have set up on your operating system, this itself does not benefit from the RAID.
Hardware RAID - the professional version
With hardware RAID you have the advantage that all calculations are done by an extra chip and your CPU is not busy with it. That's why you can use the RAID for booting and install an operating system on it, no matter which mode you need. There are RAID controllers as plug-in cards for retrofitting, but also complete RAID systems. Many NAS devices have built-in RAID controllers and therefore work quickly.
Advantages and disadvantages of hardware RAIDs
- Plus: A hardware RAID is more efficient and is already available when booting.
- Plus: It supports a variety of operating systems.
- Minus: If the controller is defective and an identical model cannot be found, the RAID becomes a data grave.
- Minus: In addition to the hard drives, there are also costs for the controller and possibly for the connection if you use an external RAID system.
In any case, you should really only consider RAID if you have a good reason for it. The disadvantages and the effort outweigh the benefits. Classic applications are video editing, when large amounts of data are no longer handled by a single hard disk, or servers. Above all, you need the greater reliability of a RAID system. A NAS with RAID 1 is an interesting alternative for private users. Read a comparison of QNAP and Synology NAS in another article.