Host Cabling For Redundancy - Dell PowerVault MD3000 Hardware Owner's Manual

Host Cabling for Redundancy

To make sure that the RAID storage array will remain accessible to the host, establish a minimum of two
physical paths from each host to the RAID controller modules. The following examples show host
cabling for redundancy.
One Host with Two Cable Connections
Figure 3-1 shows a single host with two HBAs. Both HBAs have two ports, but use only a single port.
Each HBA is connected to one RAID controller module in the RAID enclosure. Each RAID controller
module has one port.
Figure 3-1. One Host with Two Cable Connections
RAID controller module 0
This cabling topology, when used with alternate path software, ensures a redundant path from the host
server to the virtual disks. If the connection from In-0 on the RAID controller to the host port becomes
unavailable, the alternative path software will transfer I/O activity on RAID controller module 0 to RAID
controller module 1. While RAID controller module 0 is unavailable, the host can access all virtual disks
through RAID controller module 1.
One Host with Four Cable Connections
Figure 3-2 shows one host with two HBAs. Both HBAs have two ports. Each HBA port is connected to
one of the RAID controller modules in the RAID enclosure. Each RAID controller module has two ports.
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Using Your RAID Enclosure
dual-HBA host server
RAID controller module 1
MD3000 RAID Enclosure