IBM DS3500 Installation, User's, And Maintenance Manual page 73

1. In a single-controller storage subsystem, the use of redundant host connections is supported.
Redundant host connections provide path failover but limit the number of redundant host connections
to one.
2. The DS3500 ships with four storage partitions by default. For additional storage partitions, purchase
an optional Storage Partition Premium Feature upgrade. Contact your IBM reseller or marketing
representative for more information.
To connect a SAS host bus adapter (HBA) to the storage subsystem, complete the following steps:
1. Connect a SAS cable from the controller host port to the SAS HBA that is in the host. Figure 3-4 on
page 3-3 shows the location of the host ports.
2. Create a redundant host connection:
v If the storage subsystem is a single-controller storage subsystem, connect a SAS cable from the
second SAS HBA to another host port on the controller. You can create a maximum of one
redundant host connection to a single-controller storage subsystem.
v If the storage subsystem is a dual-controller storage subsystem, connect a SAS cable from the
second SAS HBA to a host port on the other controller. You can create a maximum of three
redundant host connections to a dual-controller storage subsystem.
See "Direct-attached single-controller connections" on page 3-35 and "Direct-attached dual-controller
connections" on page 3-36 for illustrations of host connections.
Starting with controller firmware version 7.77.xx.xx and later, the DS3500 also supports host connections
via SAS switch. See "Single-controller and dual-controller connections via SAS switch" on page 3-32 for
illustrations of host connections to the DS3500 SAS host port via SAS switch.
Note: For information about supported SAS switch models, SAS HBAs, and operating-system version
requirements for SAS switch connection environments, see the interoperability matrix at
http://www.ibm.com/systems/support/storage/ssic/.
Direct-attached single-controller connections:
The following illustration shows a direct-attached SAS connection to a single host HBA.
Chapter 3. Cabling the storage subsystem and storage enclosure
3-29