What is RAID?
RAID stands for Redundant Array of Independent Disks. It is a data storage technology that combines multiple disk drive components into a logical unit. RAID allows data to be distributed across multiple drives to provide increased storage capacity, faster access speeds, and/or redundancy to protect against drive failures.
There are several different RAID levels that provide various combinations of these benefits. Some common RAID levels include:
- RAID 0 – Also called disk stripping, RAID 0 spreads data across two or more drives without parity (redundancy). It provides faster access speeds but does not provide fault tolerance.
- RAID 1 – Also known as disk mirroring, RAID 1 duplicates all data from one drive to a second drive. It provides fault tolerance and protects against drive failure but does not increase storage capacity or speed.
- RAID 5 – Combines disk stripping with distributed parity, providing fault tolerance and increased storage capacity but reduced write speeds.
- RAID 10 – Combines disk mirroring and disk stripping for both performance and redundancy.
RAID is implemented in hardware or software. Hardware RAID uses a dedicated RAID controller while software RAID relies on the operating system’s software RAID driver.
What is a BIOS RAID?
A BIOS RAID is a hardware RAID that is configured using settings in the BIOS (basic input/output system) of the computer. Rather than using a separate hardware RAID controller, a BIOS RAID uses RAID capabilities built into the motherboard chipset.
The RAID configuration is done in the BIOS settings before installing the operating system. Once enabled, the BIOS RAID appears to the operating system as a single drive.
Some key advantages of a BIOS RAID include:
- Cost savings – Does not require a separate RAID controller.
- Operating system independence – Works with any operating system with BIOS RAID drivers.
- Ease of configuration – Can be set up from BIOS settings menu.
However, there are also some disadvantages to be aware of:
- Limited functionality – More advanced RAID options may not be supported.
- Slower performance – Software RAID controllers are generally slower than hardware controllers.
- No dedicated cache – Uses system RAM rather than having dedicated cache memory.
Overall, BIOS RAID provides a low cost option for basic RAID capabilities. But for more advanced configurations and better performance, a dedicated hardware RAID controller is preferable.
Should you enable BIOS RAID?
Whether you should enable BIOS RAID depends on your specific needs and setup. Here are some things to consider:
What are your goals?
If you simply need basic RAID functionality like disk mirroring (RAID 1) or disk stripping (RAID 0), a BIOS RAID may be sufficient. The built-in RAID capabilities can provide redundancy or improved speeds without additional hardware costs.
However, if you need more advanced configurations like RAID 5/6 for fault tolerance and large storage capacity, you’ll want a true hardware RAID controller. BIOS RAID options are generally limited to simpler RAID levels.
How critical are performance and reliability?
For mission critical systems that require the highest performance and reliability, most experts recommend using a dedicated hardware RAID controller instead of BIOS RAID.
The hardware controller will provide faster processing speeds, more advanced caching capabilities, and better redundancy compared to BIOS RAID. This comes at a higher cost, but for critical applications, it’s often worth the investment.
What are you using this for?
If this is for a home or small office setup mainly handling documents, media files, backups, etc., a BIOS RAID is probably sufficient. The slower speeds and lack of advanced features may not make a noticeable difference for these use cases.
For heavy workloads like managing large databases, virtual machines, media rendering, etc., the limitations of BIOS RAID are more likely to impact performance. A true hardware RAID controller would be better suited for these scenarios.
What is your budget?
One of the main appeals of BIOS RAID is that it allows you to add RAID capabilities without buying an expensive controller card. If cost is a major factor, leveraging your motherboard’s built-in RAID support can save several hundred dollars or more.
For well-funded setups where performance matters more than squeezing every dollar, investing in a robust RAID controller instead of relying on BIOS RAID makes more sense. The higher upfront cost brings advantages that can pay off long-term.
Pros of enabling BIOS RAID
Using your motherboard’s built-in BIOS RAID capabilities offers some benefits:
Cost savings
There’s no need to purchase a separate RAID controller card which can easily cost $200 or more depending on the features. BIOS RAID provides basic RAID functionality using existing hardware.
Operating system independence
BIOS RAID works with any operating system that has BIOS RAID driver support. This includes Windows, Linux, FreeBSD, etc. Dedicated RAID controllers may have some OS limitations.
Easy to configure
The RAID array can be setup right from the BIOS menu before installing the OS. No special utility software is required. The RAID appears to the OS as a standard drive.
Provides basic RAID functionality
Common RAID levels like 0, 1 and 10 are typically supported for added capacity, redundancy, or performance. Enough for many home and small business setups.
Scalability
Storage capacity can be increased by adding more supported hard drives to the array. Extra drives can be added live without needing to rebuild the array.
Cons of enabling BIOS RAID
While BIOS RAID can be convenient, some drawbacks include:
Slower performance
The software RAID controller implemented in the BIOS generally provides much lower performance compared to a dedicated hardware RAID card. The impact is very noticeable under heavy workloads.
Limited RAID options
More advanced RAID levels like 5, 6, 50, 60 may not be supported and configuring hot spares is often not an option. Manageability and monitoring capabilities are also limited.
No cache or battery backup
Hardware RAID cards have onboard cache memory and battery backup units to preserve data in case of power failure. BIOS RAID lacks these protections.
Uses system resources
With no dedicated processing hardware, BIOS RAID utilizes your system’s CPU, RAM and other resources which can negatively impact performance of other tasks.
Not ideal for mission critical systems
While fine for personal use, most experts don’t recommend relying on BIOS RAID for business-critical data that requires maximum reliability and uptime. The hardware controller redundancy is preferred.
RAID management can require opening computer
Changing existing RAID configurations may require entering the BIOS setup menu meaning you need physical access to the machine which can be inconvenient if it’s in a remote rack or server room.
Key factors to consider
If you’re debating between BIOS RAID and a dedicated hardware controller, take these key factors into account:
Onboard RAID chipset
The RAID functionality can vary greatly depending on the motherboard chipset. Higher end server boards tend to offer more robust BIOS RAID capabilities that close the gap somewhat with hardware controllers.
Supported RAID levels
Make sure the motherboard supports all the RAID configurations you need. Entry-level boards may only support RAID 0 and 1. Maximum number of allowable disks per array also varies.
I/O performance requirements
BIOS RAID I/O speeds often top out at 1-2 GB/s. Multiple enterprise SSDs can saturate this easily. High speed disk arrays may require a hardware controller to reach full potential.
Server vs desktop use
For home desktops mainly handling lighter workloads, BIOS RAID can provide enough functionality. But for servers under constant heavy loads, the limited performance can become a bottleneck.
Recommendations
Based on your specific needs and setup, here are some recommendations on whether to enable BIOS RAID or use a hardware controller:
Use BIOS RAID if you…
- Only need basic mirroring or striping (RAID 0/1).
- Primarily store media files, documents, backups.
- Need to save costs on your PC build or upgrade.
- Don’t require advanced RAID management capabilities.
Use hardware RAID if you…
- Require RAID 5/6/10/50/60 configurations.
- Need maximum performance for transactional workloads.
- Have business critical data requiring high availability.
- Prefer advanced monitoring, caching, and management features.
As a general rule of thumb, BIOS RAID capabilities have improved enough over the years for many personal and small business use cases. But for specialized applications with intensive I/O demands, hardware RAID still provides the best combination of performance, protection and scalability.
Conclusion
Enabling BIOS RAID allows you to leverage your motherboard’s built-in RAID capabilities for an inexpensive way to implement basic RAID configurations like disk mirroring or striping. This can provide added redundancy or performance without requiring a dedicated controller.
However, for mission critical environments, hardware RAID controllers remain the preferred solution. The hardware acceleration and more robust feature sets better support demanding workloads, complex RAID configurations, and enterprise-class availability needs.
Carefully consider your performance requirements, RAID needs, budget and internal PC hardware when deciding between BIOS RAID and hardware controllers. For many home and small business PCs, BIOS RAID provides satisfactory disk performance and protection. But for specialized applications and large scale server deployments, purpose-built hardware RAID cards are worth the additional investment.
