📖 What is RAID (Redundant Array of Independent Disks)?
RAID is a storage virtualization technology that combines multiple physical disk drive components into one or more logical units for data redundancy or performance improvement. It protects against data loss by mirroring or striping data across several physical disks in an array.
"Focus on RAID 0 (striping), RAID 1 (mirroring), RAID 5 (striping with parity), and RAID 10 (mirroring and striping) for the exam."
📚 Certification: CompTIA A+ Certification Exam Core 1 (220-1101)
🔑 What are the Key Concepts of RAID (Redundant Array of Independent Disks)?
- ▸ RAID 0 uses striping to distribute data across disks, maximizing read/write speeds but providing no fault tolerance if a drive fails.
- ▸ RAID 1 employs mirroring to create an exact duplicate of data on two disks, ensuring high availability and complete data redundancy.
- ▸ RAID 5 combines striping with parity, allowing the array to survive a single drive failure while maintaining efficient storage capacity.
- ▸ RAID 10 integrates mirroring and striping, offering the high performance of RAID 0 and the redundancy of RAID 1.
- ▸ Hardware RAID uses a dedicated controller to manage the array, whereas software RAID relies on the operating system and CPU.
🎯 How does RAID (Redundant Array of Independent Disks) appear on the 220-1101 Exam?
You may be asked to recommend a RAID level for a user who prioritizes maximum disk performance and does not require data redundancy.
A scenario might describe a server that must survive a single drive failure without losing data while maximizing available storage space.
Expect questions where you must choose the most resilient and high-performance option for a critical database, requiring at least four disks.
❓ Frequently Asked Questions
What happens to the data in a RAID 0 array if one disk fails?
In RAID 0, there is no redundancy. Because data is striped across all disks, the failure of a single drive results in the total loss of all data on the array.
Why is RAID 5 often preferred over RAID 1 for larger storage arrays?
RAID 1 mirrors everything, wasting 50% of total capacity. RAID 5 uses parity, providing redundancy while allowing significantly more usable storage space as more disks are added.
How many disks are required to implement RAID 10?
RAID 10 requires a minimum of four disks because it first mirrors pairs of disks (RAID 1) and then stripes data across those mirrored sets (RAID 0).