Chapter 4. IBM System Storage DS3500 and EXP3500 Cabling 109
Figure 4-21 An example of a multi-host, multi-port and multi-fabric host configuration
Before you attach hosts to the storage subsystem, you should always ensure that the host
systems and host bus adapters (HBAs) are installed correctly and updated with the supported
firmware and drivers levels. The supported levels are documented in the readme files that
come with the version of DS3500 firmware and DS Storage Manager that you want to use.
4.8.1 SAS attachment
Host server SAS HBAs are used to connect to the DS3500 SAS ports. Each DS3500
controller can have up to four SAS host ports when you install the optional SAS host interface
adapter. When the optional SAS host interface adapter is installed, the DS3500 can support
up to 28 Blade Center hosts when attached to the SAS Connectivity Module for IBM Blade
Center and up to four hosts in a direct attached host environment.
Always use redundant host connections. The use of redundant host connections with a single
controller DS3500 storage subsystem is supported but limits the number of hosts to a
maximum of two if the optional SAS host card is installed in the DS3500.
SAS host attachment examples
In this section we show examples of SAS host attachment with single and dual controller
DS3500 storage subsystems.
Figure 4-22 on page 110 shows the simplest host attachment method: a single host server
with one SAS host bus adapter connecting to a single controller DS3500 storage subsystem.
General rule: Although the example shown in Figure 4-22 on page 110 is a valid
supported configuration, there is no redundancy of host side connections. Always use
redundant host side connections instead.