Dot Hill Systems II 200 FC Additional Software Tools, Active-to-Active Redundant Controller

1.5.1.2Active-to-Active Redundant Controller

In active-to-active redundant controller mode, the primary loop serves the I/O traffic directed to the primary controller, and its pair loop serves the I/O traffic to the secondary controller. The host-side management software directs I/O traffic to the pair loop if one of the redundant loops fails.

Since each fibre interface supports only a single loop ID, two HBAs are necessary for active-to-active redundant controller operation. Using two HBAs in each server ensures continued operation even when one data path fails.

In active-to-active mode, the connection to each host adapter should be considered a data path connecting the host to either the primary or the secondary controller. One adapter should be configured to serve the primary controller and the other adapter to serve the secondary controller. Each target ID on the host channels should be assigned either a primary ID or a secondary ID. If one controller fails, the remaining controller can inherit the ID from its counterpart and activate the standby channel to serve host I/O.

1.5.1.3Host Redundant Paths

The controller passively supports redundant fibre loops on the host side, provided that the host has implemented software support for this feature.

In the unlikely event of controller failure, the standby channels on the remaining controller become an I/O route serving the host I/O originally directed to the failed channel on its pair of controllers. Application failover software should be running on the host computer to control the transfer of I/O from one HBA to another in case either data path fails.

1.6Additional Software Tools

The following additional software tools are available:

■SANscape, a management and monitoring program

■SANscape Alert, a monitoring utility

■SANscape CLI, a command-line utility to monitor and manage the array.

Refer to the SANscape Software Installation Guide for information about installing these tools.

For additional information, refer to the release notes in the SANnet II 200 array hardware section at the following web site: http://www.dothill.com/manuals.

Chapter 1 Product and Architecture Overview 1-15