Disk array controller: Difference between revisions

Revision as of 18:25, 26 January 2023

Revision as of 16:25, 10 August 2023

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== Front-end and back-end side ==

A disk array controller provides front-end interfaces and back-end interfaces.

* BackThe back-end interface communicates with the controlled disks. Hence, its protocol is usually [[Advanced Technology Attachment|ATA]] (a.k.a. PATA), [[Serial ATA|SATA]], [[SCSI]], [[Fibre Channel|FC]] or [[Serial Attached SCSI|SAS]].

* FrontThe front-end interface communicates with a computer's [[host adapter]] (HBA, Host Bus Adapter) and uses:

** one of ATA, SATA, SCSI, FC; these are popular protocols used by disks, so by using one of them a controller may transparently [[emulator|emulate]] a disk for a computer.

** somewhat less popular protocol dedicated protocols for a specific solutionsolutions: [[FICON]]/[[ESCON]], [[iSCSI]], [[HyperSCSI]], [[ATA over Ethernet]] or [[InfiniBand]].

A single controller ''may'' use different protocols for back-end and for front-end communication. Many enterprise controllers use FC on front-end and SATA on back-end.