📖 What is RAID?
RAID (Redundant Array of Independent Disks) is a data storage technology that combines multiple physical drives into a single logical unit to improve performance, increase storage capacity, and/or provide data redundancy. Different RAID levels offer varying balances of these benefits.
"Prioritize understanding RAID 0 (striping), RAID 1 (mirroring), RAID 5 (striping with parity), and RAID 10 (mirroring and striping). Know the fault tolerance, performance characteristics, and minimum drive requirements for each level. Questions often involve selecting the appropriate RAID level for a given scenario."
📚 Certification: CompTIA A+ Certification Exam Core 2 (220-1102)
🔑 What are the Key Concepts of RAID?
- ▸ RAID 0 increases performance by striping data across multiple drives, but offers no redundancy – a single drive failure results in total data loss.
- ▸ RAID 1 mirrors data onto two or more drives, providing excellent redundancy but reducing usable storage capacity by half (or more).
- ▸ RAID 5 distributes data and parity information across multiple drives, offering a good balance of performance, capacity, and fault tolerance.
- ▸ RAID 10 (or RAID 1+0) combines mirroring and striping for both performance and redundancy, requiring a minimum of four drives.
- ▸ Understanding minimum drive requirements and the impact of drive failure on each RAID level is crucial for exam success.
🎯 How does RAID appear on the 220-1102 Exam?
You may be asked to identify the RAID level that provides the best data protection for a critical database server, even if it means sacrificing some storage capacity.
A scenario might describe a workstation needing maximum performance for video editing – determine which RAID level would be most suitable.
Expect questions about calculating usable storage capacity given a specific RAID level and the size of the constituent drives.
❓ Frequently Asked Questions
What's the difference between RAID 5 and RAID 6?
RAID 6 adds a second parity scheme, allowing it to tolerate two simultaneous drive failures, unlike RAID 5 which can only handle one. This increases redundancy but also adds overhead.
Can software RAID provide the same performance as hardware RAID?
Generally, hardware RAID offers better performance because it has a dedicated processor. Software RAID relies on the CPU, potentially impacting system performance, but is often more affordable.
If a drive fails in a RAID 5 array, how does the system continue to operate?
RAID 5 uses parity to reconstruct the missing data on the fly. The system operates in a degraded mode until the failed drive is replaced and the array is rebuilt.