📖 What is RAID 1 (Redundant Array of Independent Disks 1)?
RAID 1 (Redundant Array of Independent Disks 1), known as mirroring, duplicates data across two or more disks. This provides high data redundancy, ensuring that if one drive fails, the system remains operational using the mirrored copy.
"Mirroring requires double the storage capacity for the same amount of data, but it is the safest basic option for critical data."
📚 Certification: CompTIA A+ Certification Exam Core 1 (220-1101)
🔑 What are the Key Concepts of RAID 1 (Redundant Array of Independent Disks 1)?
- ▸ Mirroring involves writing the exact same data to two or more disks simultaneously, ensuring a complete duplicate exists at all times.
- ▸ High fault tolerance allows the system to continue operating without downtime if one drive fails, as the second drive takes over immediately.
- ▸ Storage efficiency is low because the total usable capacity is equal to the size of the smallest single drive in the array.
- ▸ Read performance may increase because the system can read data from either disk, though write speeds remain similar to a single drive.
- ▸ Rebuilding the array requires replacing the failed drive and allowing the controller to copy all data from the healthy disk to the new one.
🎯 How does RAID 1 (Redundant Array of Independent Disks 1) appear on the 220-1101 Exam?
You may be asked to recommend a RAID level for a client who prioritizes data redundancy and uptime over storage capacity and high-speed performance, specifically for a critical server containing essential business records.
A scenario might describe a technician installing two 4TB drives in a mirrored configuration; you will be asked to identify the total usable storage capacity, which would be 4TB, not 8TB.
Expect questions where you must distinguish between RAID 0 and RAID 1 based on whether the primary goal is increasing disk I/O speed or ensuring data availability during a hardware failure.
❓ Frequently Asked Questions
How does RAID 1 differ from RAID 0 in terms of risk?
RAID 0 increases risk because a single drive failure results in total data loss. RAID 1 eliminates this risk by mirroring data, allowing the system to survive the loss of one drive without losing information.
Can RAID 1 be used as a substitute for a backup strategy?
No. RAID 1 provides hardware redundancy, not a backup. If a file is accidentally deleted or corrupted by malware, that change is mirrored instantly to both disks, making the data unrecoverable without a separate backup.