Error Message :
N/A
According to Automic's Workload Automation Administration Documentation Guide if CAU_PARALLEL_LIMIT is set to 0 it will disable CAU.
However, this is not 100% accurate.
Investigation
Inaccurate section of the documentation:
This key sets a limit for the number of agents that can be upgraded in your system at the same time during a Centralized Agent Upgrade (CAU).
! The value is applied per platform (Windows or UNIX). Therefore, if you upgrade two different platforms at the same time, in each 1000 agents will be upgraded (default value).
! If you set this value to "0" the CAU will be disabled, since no agent will be upgraded.
Allowed values: 0 to 100000
Default value: 1000
The documentation should say: This key sets a limit for the number of agents that can be upgraded in your system at the same time during a Centralized Agent Upgrade (CAU).
! The value is applied per platform (Windows or UNIX). Therefore, if you upgrade two different platforms at the same time, in each 1000 agents will be upgraded (default value).
! If you set this value to "0" the CAU will be disabled and no agent will be upgraded. This only applies to manual upgrades initiated by AWI users and not to the automatic mechanism which currently cannot be disabled using this parameter. As a workaround you can rename the corresponding storage object in client 0.
Allowed values: 0 to 100000
Default value: 1000