Redundancy; Redundancy Scenarios - Alcatel-Lucent OmniSwitch AOS Release 7 Manual

Managing CMM Directory Content

Redundancy

CMM software redundancy is one of the switch's most important fail over features. For CMM software
redundancy, two fully-operational CMM modules must be installed at all times. In addition, the CMM
software must be synchronized. (Refer to
page 3-19 for more information.)
When two CMMs are running one CMM has the primary role and the other has the secondary role at any
given time. The primary CMM manages the current switch operations while the secondary CMM provides
backup (also referred to as "fail over").

Redundancy Scenarios

The following scenarios demonstrate how the CMM software is propagated to the redundant CMM In the
examples below, R represents the RUNNING-CONFIGURATION directory and C represents the certi-
fied directory.
Scenario 1: Booting the Switch
The following diagram illustrates what occurs when a switch powers up.
Scenario 2: Rebooting from the Working Directory
After changes to the configuration and image files are saved to the working directory, sometimes it is
necessary to boot from the working directory to check the validity of the new files. The following diagram
illustrates the synchronization process of a working directory reboot.
OmniSwitch AOS Release 7 Switch Management Guide
"Synchronizing the Primary and Secondary CMMs" on
CMM A
C R
1. Switch is pow-
ered up and boots
from the certified
directory which
becomes the run-
ning-configura-
tion.
Powering Up a Switch
CMM B
R
2. The running-
configuration is
automatically syn-
chronized to the
secondary CMM.
March 2011
CMM Files
page 3-9