Adaptec 1966600 User Guide - Page 86

DuraStor 6220SS/7220SS Installation and User's Guide Hubs Disabled (Single External Hub) Figure 3-47 shows the hosts in a single loop using an external hub connected to the DuraStor 7220SS storage subsystem's two controllers. From a controller failover perspective, this configuration operates much the same as the previous configuration which uses a switch. The advantage of using a hub is that it is less expensive. In active-active dual-port mode, you must deal with the cost of host software and multiple images of the same LUN. DuraStor FC RAID Appliance Host 1 Host Link 1 FC HBA Host 2 P2 Hub P1 P3 FC HBA P4 Host Link 2 LUN 2 CH0 FC2 Passive CH1 FC1 LUN 2 Active CH2 Controller 2 CH3 LUN 1 FC1 Active FC2 LUN 1 Passive Controller 1 CH0 T CH1 T CH2 T CH3 T CH0 Up to 12 Disk Drives CH1 Up to 12 Disk Drives CH2 Up to 12 Disk Drives CH3 Up to 12 Disk Drives Figure 3-47 Active-Active Single-Port Hubs Disabled, Single External Hub Hubs Enabled Figure 3-48 shows the hosts in a single loop connected to the DuraStor 7220SS storage subsystem's controllers with the internal hubs enabled. The internal hub circuits eliminate the need for an external hub. This allows one or two hosts to be connected to the 3-52