StorCase Technology CSI-to-SCSI Single & Dual RAID - Manual (Page 108)

Dual RAID Module User's Guide - Rev. A03 StorCase Technology, Inc.
Configuration 95
Active-Active Operation Scenarios
Dual Boot - When both controllers boot at the same time, they exchange information
related to their current configuration and the ownership of resources. The
time and date of Controller B is synchronized with that of Controller A.
Add Array - When a controller adds an array, that controller is owner of the array (as
well as any dedicated spare drives). Arrays and dedicated spares are
not visible to the other controller when both controllers are online.
Delete Array - A controller may only delete arrays that it owns.
Pool Spare - Pool spares are visible to both controllers when both controllers are online.
Configuration
Failover -
When a failover occurs, the surviving controller will display "FAILED
OVER" on the Disk Array Administrator (in the area between the board
temperature and date). At this point, the arrays, dedicated spares, and
pool spares of the failed controller now belong to the surviving controller.
Resources from the failed controller are tagged with (FO).
Failback - When a failback occurs, the controller coming online regains control of its
arrays, dedicated spares, and pool spares from the other controller.
Changing the Operating Mode
NOTES: Default operating mode for the Dual RAID Module Unit is Active-Passive.
Default operating mode for the Single RAID Module Unit is Stand-Alone
Dual Port.
Default operating mode for the Single RAID Module Upgrade is Stand-Alone
Dual Port.
This function allows the user to change the controller's operating mode. In a dual controller
configuration (Active-Active or Active-Passive mode), a change to either controller's setting
is immediately sent to the other controller (unless changed to the Stand Alone mode).
CAUTION: When using any dual port mode, the host operating system and drivers
must support dual port accesses. If the host system does not support dual
port access, do not configure the controller in dual port mode, because
the O/S may believe that a single LUN is really two independent arrays
(resulting in possible data corruption).