RAID 1 Explained: Mirroring for Data Redundancy

RAID 1, also known as disk mirroring, is a data storage technique that creates an exact copy of data on two or more separate hard drives simultaneously. This means every piece of data written to one drive is duplicated on the other(s), providing high data redundancy and fault tolerance. If one drive fails, the system can continue operating using the mirrored drive(s) without data loss.

Key aspects of RAID 1 include:

• Data Redundancy: Each drive contains an identical copy of the data, ensuring continuous availability even if a drive fails.
• Fault Tolerance: The system can withstand the failure of one drive without interrupting data access.
• Read Performance: Read operations can be faster because data can be read from any of the mirrored drives, potentially distributing read requests.
• Write Performance: Write speed may be slightly slower since data must be written to all drives simultaneously.
• Storage Efficiency: The usable storage capacity is effectively halved because data is duplicated. For example, two 1 TB drives in RAID 1 provide 1 TB of usable space.

RAID 1 requires at least two drives but can include more, with all drives containing identical data copies. It is commonly used in environments where data integrity and availability are critical, such as database systems and financial records.

Unlike RAID levels that use striping or parity, RAID 1 does not split data across drives but mirrors the entire data set on each drive. This simplicity makes it reliable and easy to manage, though at the cost of storage efficiency. Some RAID 1 implementations support automatic failover and hot swapping of failed drives, enhancing system uptime.