What is RAID?
RAID (Redundant Array of Independent Disks) is a data storage technology that combines multiple physical disk drives into a single logical unit to improve performance, increase storage capacity, or provide data redundancy — or a combination of these benefits.
How Does RAID Work?
RAID works by distributing or replicating data across multiple drives according to different configurations called RAID levels. RAID 0 stripes data across drives for maximum performance but offers no redundancy. RAID 1 mirrors data across two drives, providing full redundancy at the cost of halving usable capacity. RAID 5 distributes data and parity information across three or more drives, tolerating a single drive failure while preserving most of the storage capacity. RAID 10 combines mirroring and striping for both performance and redundancy.
In web hosting environments, RAID is standard practice for protecting against data loss from drive failures. Enterprise servers commonly use RAID 5, RAID 6 (which tolerates two simultaneous drive failures), or RAID 10. Hardware RAID controllers handle the array management transparently, while software RAID implementations are available in most operating systems. While RAID protects against hardware failures, it is not a substitute for proper backups — it cannot protect against accidental deletion, corruption, ransomware, or catastrophic events affecting the entire server.