Adaptec 412R User Guide - Page 195

Glossary A active-active Active-active mode is when two controllers in an external subsystem cooperate to provide redundancy. If one controller fails, the remaining controller will take over the failed controller's functionality. To accomplish this, each controller has two host SCSI ports, one of which is normally active, the other normally passive. In a failed-over configuration, the passive port becomes active and assumes the identity of the failed controller. In active-active mode, arrays can be accessed only by the controller that currently owns them. One controller will have no visibility of the other controller's arrays. Disk drives in the spare pool and unassigned disk drives are visible to both controllers. array Two or more physical drives grouped together to appear as a single device (logical drive) to the user. Also known as a container. B bus See channel. C channel Any path used for the transfer of data and the control of information between storage devices and a storage controller. Each controller's channels are identified by a number. They are numbered in enter short product name starting with number 0. Also known as a bus. See also LUN (logical unit number). Glossary-1