Auto Unit Replacement - Avaya 4524GT Configuration Manual

System configuration fundamentals

Auto Unit Replacement

You can use the Auto Unit Replacement (AUR) feature to replace a unit from a stack while
retaining the configuration of the unit. This feature requires the stack power to be on during
the unit replacement.
The main feature of the AUR is the ability to retain the configuration (CFG) image of a unit in
a stack during a unit replacement. The retained CFG image from the old unit is restored to the
new unit. Because retained CFG images are kept in the DRAM of the stack, the stack power
must be on during the procedure.
Important:
For Auto Unit Replacement to function properly, the new unit and the existing units in the
stack must all run the same version of software and diagnostic. In case of a two high stack,
only replacing a non-base-unit is currently supported.
You can manually restore an associated configuration (same unit number) of a unit in a stack
including base unit (if the stack is of 3 units or bigger).
Important:
If the base unit is reset before you restore the configuration, the base unit erases the saved
configuration information for non-base units.
The following information also relates to this feature:
• The new unit must be the same hardware configuration as the old, including the same
number of ports.
• If the administrator adds a new unit with a different hardware configuration, the
configuration of this unit is used.
• If the administrator adds a new unit with the same hardware configuration, the previous
configuration of the new unit is lost. The configuration is overwritten with the restored
configuration from the stack.
• You can enable or disable this feature at any time using ACLI. The default mode is
ENABLE.
• Customer log messages are provided.
Important:
After booting a stack, use ACLI command show stack auto-unit-replacement from
a unit console to find out if that unit is ready for replacement.
The ACLI command show stack auto-unit-replacement provides the following
information:
18 Configuration — System April 2011