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Chapter 2
Installation
2-43
Note –
This completes the installation process for a single disk tray installation. If
you are configuring a partner group, you must continue to the next section.
2.12.4
Establishing Alternate Pathing on the Host
This task applies only when two controller units are configured as a partner group.
In a partner group, controller caches are mirrored so that if one controller fails, no
data is lost. Any data that is in the cache of the failed controller but is not yet written
to disk is preserved in the cache of the partner controller and is written to disk by
means of one of the back-end Fibre Channel loops connecting the two units.
The back-end Fibre Channel loops are used to maintain host access to the disks of
the unit with the failed controller (or any failure in the host data path to that
controller). This requires the use of a host-based alternate pathing mechanism such
as the dynamic multipathing (DMP) feature of VERITAS Volume Manager or the
Solaris alternate pathing software. When a failure occurs in the host data path, the
alternate pathing mechanism reroutes data to the other disk tray controller in the
partner group. The controller then redirects the data across one of the back-end
loops to the disks of the other controller, thus maintaining data availability to the
host application.
For more information and for instructions on installing and configuring alternate
pathing, refer to the documentation for the alternate pathing tool selected.
For the alternate pathing software to function properly, you must enable
multipathing support on the disk tray for partner group configurations. To do so,
use the following procedure:
1. If you are not already in a telnet session with the disk tray, start one.
If you are in a telnet session, skip to Step 2.
a. On the host, use the
telnet
command with the disk tray name (or IP address)
to connect to the disk tray.
b. Log in to the disk tray by typing
root
and your password at the prompts.
# telnet
disk-tray-name
Trying 129.150.47.101...
Connected to 129.150.47.101.
Escape character is ’^]’.
pSOSystem (129.150.47.101)
Summary of Contents for Sun StorEdge T3
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