Key Differences Between Software RAID and Hardware RAID
In recent years, companies have continued to add software components to their storage infrastructure. This includes RAID to maximize storage capacity and reduce the risk of data loss. Some organizations are moving from hardware RAID to software RAID arrays.
The main difference between software RAID and hardware RAID is that operating system software manages the former, while controllers independent of the operating system manage the latter. They are also different in terms of cost, performance and access speeds.
RAID is a virtual storage resource using multiple storage devices – the array – managed by a controller that attaches one or more computing devices to the array. RAID presents disks to users as logical storage resources. Many different options for RAID storage are available, and costs can vary as widely as the available selection of devices and controllers.
When RAID first appeared on the market, it used a hardware configuration. RAID offerings included storage devices and the controller, which connects to one or more computers and multiple storage devices in the array. Figure 1 illustrates a hardware RAID array.
Configure all RAID related components for specific user needs and RAID level. Organizations can make changes to a disk array and controller independent of computing devices.
The advantages of hardware RAID are:
- Hardware RAID data access is generally faster.
- The controller manages the disks independently of the associated computer and does not need to use processing power.
- It is easy to replace a failed drive by removing and replacing the device.
The disadvantages of hardware RAID are:
- Although hardware RAID is often more reliable because it doesn’t take away processing power from the disks, it can be more expensive than software RAID.
- It may not be compatible with the associated operating system.
- Performance issues can arise when using different technologies such as SSDs.
In contrast, software RAID embeds disk controller software into the computer system and must be compatible with the operating system. Figure 2 illustrates a software RAID array.
As with hardware systems, configure software components related to RAID for specific user needs. Changes to the disk array and controller require more user interaction with the operating system because the RAID controller is part of the operating system.
The advantages of software RAID are:
- It is generally less expensive than hardware RAID because no RAID controller is needed.
- The controller manages the disks as part of the associated computer.
- Software RAID can be implemented in one operating system and used by multiple devices.
The disadvantages of software RAID are:
- Data access may be slower compared to hardware RAID.
- Connected devices must be compatible with the associated operating system.
- Replacing a disk is more complex because the operating system must tell the RAID controller to shut down.
Comparison of Software RAID and Hardware RAID
To choose between hardware RAID and software RAID, consider the following categories and features.
Performance and flexibility
- Use hardware RAID when high performance and flexibility are required or when a high-level RAID implementation is needed.
- The performance of software RAID is comparable to hardware RAID but may be limited because it shares the processing overhead of the operating system.
- Hardware RAID can be more expensive than other options.
- Software RAID does not require a separate controller, reducing costs.
- Hardware RAID requires a RAID controller. Replace RAID controllers with a similar unit if a controller is lost.
- Software RAID does not use an external controller.
- Hardware RAID speeds are dependent on controller, network, and number or types of disks.
- Software RAID access speeds can be as fast or faster than hardware-based controller software and disks.
- Hardware RAID operates independently of the operating system. Multiple operating systems can share a hardware RAID.
- Software RAID uses a driver in the operating system and uses the associated operating system.
Reasons to use RAID storage
Both hardware and software RAIDs support most storage requirements if configured to user specifications. Add more disks to the array to increase storage capacity.
RAID also provides primary storage and secondary support for applications, as well as files and databases. They are important components of an organization’s data protection and disaster recovery strategies. Although they provide additional support for data protection and disaster recovery, implementing RAID should not be the primary data backup and disaster recovery strategy.
Another option: Hybrid RAID
Hybrid RAID uses the capabilities of both hardware and software RAID systems. For example, organizations can implement a hardware configuration that connects its controller to the operating system to augment software RAID. This provides the flexibility to support different operating systems.
Although hybrid RAID may be a viable approach, check storage configuration and performance capabilities before investing.