Connectors, switch, and enclosure ID
The controllers support fiber-optic interfaces for both the host channel and drive
channel ports. The controllers also contain two Ethernet ports for storage
subsystem management purposes and a serial port that IBM Support uses to
perform problem recovery and troubleshooting procedures.
The default IP addresses for the Ethernet ports on controller Aare 192.168.128.101
and 192.168.129.101. The default IP addresses for the Ethernet ports on controller
B are 192.168.128.102 and 192.168.129.102. The subnet mask for all cases are
255.255.255.0. See “Setting up IP addresses for DS5020 storage controllers” on
page 11 for more information.
The enclosure ID, comprised of two seven-segment numbers, is located on the
back of each controller next to the controller indicator lights. The two digits that
comprise the enclosure ID are referred to as x10 and x1 digits. The enclosure ID
provides a unique identifier for each enclosure in the storage subsystem. The
storage management software automatically sets the enclosure ID number. Youcan
only change the enclosure ID setting through the DS Storage Manager software.
There are no switches on the DS5020 chassis to manually set the enclosure ID.
Both controller enclosure ID numbers will be identical under normal operating
conditions. The default setting of the enclosure ID is a value of 85.
Storage expansion enclosures in a DS5020 storage subsystem must also have
unique enclosure IDs. In addition to having unique enclosure IDs for each storage
expansion enclosure (including the DS5020 storage subsystems with drives
installed) in the DS5020 storage subsystem configuration, make sure that the single
digit (x1) of the enclosure ID for every storage expansion enclosure in a redundant
drive channel/loop pair is unique.
If you do not set the single-digit value of the enclosure IDs to be unique among
storage expansion enclosures in a redundant drive channel/loop pair, it will be
difficult to troubleshoot the source of errors in the drive channels. For example, with
four enclosures attached to a DS4500 in a redundant drive loop pair, the correct
enclosure ID settings are x1, x2, x3, and x4 (where x can be any digits that can be
set). Examples of incorrect settings would be 11, 21, 31, 41; or 12, 22, 32 62.
These examples are incorrect because the x1 digits are the same in all enclosure
IDs (either 1 or 2).
If the enclosure IDs in your subsystem configuration are not currently set to have
unique single-digit (x1) values for the enclosures in the same redundant drive
channel/loop pair, make the changes to the enclosure IDs in the next maintenance
schedule. The EXP520 and EXP810 storage expansion enclosures do not require
you to reset the power to the configuration to activate new enclosure ID settings.
Figure 2 on page 10, Figure3 on page 10, and Figure 4 on page 10 show the three
different DS5020 controller configurations that are available. Figure 2 on page 10
shows the base DS5020 storage subsystem, with two Fibre Channel host ports. For
more information about DS5020 controller options and other components, see the
“Parts listing” on page 160.
Chapter1. Introduction 9