RAID 5 definition
RAID 5 is a storage configuration that stripes data across three or more drives while distributing parity information among them. If one of the drives fails, the data can be reconstructed from the remaining drives using the parity.
See also: NAS, fault tolerance, data center storage, hot spare
Raid 5 usage
RAID 5 is popular in environments that require a balance between performance, storage efficiency, and fault tolerance. However, modern hard drives have considerably increased in size, which lead to longer rebuild times for a RAID 5 array after a disk failure. The window of vulnerability — where a second disk failure could result in data loss — has also grown.
Critical systems prefer RAID 6, which tolerates the simultaneous failure of two disks.
- Business servers. Many medium-sized businesses use RAID 5 for their servers to ensure data availability.
- File and application servers. For general-purpose file storage and application hosting, RAID 5 provides an efficient use of disk space and protection against single disk failure.
- Database systems. Some database systems use RAID 5, especially when read operations significantly outnumber write operations. However, other RAID levels or storage configurations are more appropriate for databases with heavy write loads due to the write penalty in RAID 5.
- NAS (network-attached storage) devices. Many consumer and business-class NAS devices offer RAID 5 configurations for a balance of storage capacity and redundancy.
- Video production. For video editing workflows where large amounts of data need to be read quickly and where data protection is essential, RAID 5 is a viable choice.
- Archival storage. Data protection is essential in some archival systems, but the highest possible performance isn't critical. This makes RAID 5 a cost-effective choice.
