Definition
A redundant array of independent disks (RAID 4) is a storage setup that partitions data into blocks across numerous disks, with a separate disk solely dedicated to storing parity data. This configuration ensures fault tolerance and data integrity.
RAID 4 Structure
In RAID 4 configurations, data undergoes a process known as data striping, where it’s divided into blocks, and each block is written to a separate disk drive. For instance, if we have data blocks A, B, C, and D spread across four disks, block A would be stored on Disk 1, block B on Disk 2, block C on Disk 3, and block D on Disk 4.
In contrast to the uniform distribution of data blocks, RAID 4 designates a specific disk solely for storing parity information. The parity information helps to reconstruct data from the surviving disks if one malfunctions.
RAID4 Functions
- Fault tolerance: The dedicated parity disk ensures RAID array continuity even if the data disks fail.
- Performance: The striping enables the read operations to be fast because multiple disks because several disks can be read concurrently. Unfortunately, RAID 4 write operations are slower than other RAID setups. This is because the parity must be updated every time data is written on a disk.