In computing, a disk array controller is a computer hardware device which provides secondary storage services to computer systems, often in large servers. It is the critical component of a disk array.

A disk array controller usually attaches to a number of disk drives in disk enclosures which are organised into RAID sets or groups for data protection and performance reasons.

Disk array controllers often provide other services in addition to RAID arrays. These include a read cache , a fast write cache , and copy services such as Flash Copy and Peer to Peer Remote Copy (PPRC ). Various vendors have different terms for these concepts.

Disk array controllers attach to computers using a number of different methods. These include:

• Parallel SCSI buses, including the newer wide, fast, and ultra versions of parallel SCSI.
• ESCON or FICON for connecting to a mainframe computer
• The SCSI command protocol over a Fibre Channel link
• a SAN over either an IP Network (iSCSI) or Fibre Channel

See also

• Disk array - the field of business-class data storage
• Disk enclosure - the field of business-class data storage
• Enterprise storage - the field of business-class data storage
• RAID - Redundant Array of Independent Disks
• Fibre Channel - Most often used protocol to implement a SAN.
• iSCSI - attempt to re-unify storage and communication networks.
• Network attached storage (NAS)
• SCSI - a standard for computer communication