This document is created as a result of a customer issue: an AL 3.7 XEN-based 6-node grid and the UI Dashboard shows only 40 (out of total 48) CPU cores free if there is only one application running on this grid and it is using only 1 CPU.
It turns out that this is because in XEN-based Applogic 3.7 each node of the grid is by default assigned 1 CPU core for dom0 and in addition, on the primary node there is 1 full CPU core assigned to the grid controller. Command "server info" run on the grid controller for each node will show 2 CPU cores reserved for the primary node and 1 CPU core reserved for all other nodes.
So even if there is no application running on the grid, UI dashboard will show that <#_of_nodes_in_the_grid + 1> CPUs are in use.
This is new behavior in Applogic 3.7. In older versions CPU cores were shared between applications, dom0 and grid controller.
In pre-3.7 version "server info" command for primary node would show only 0.10 CPU reserved for grid controller:
--- Resource Information ---
Resource Count Total Reserved Alloc Hypervisor Free
-------------------------------------------------------------------------------------
CPU 4 16.00 0.10 3.55 - 12.35
In 3.7 version output of "server info" for primary node looks like this (showing 1 CPU reserved for dom0 and 1 for controller):
--- Resource Information ---
Resource Count Total Reserved Alloc Hypervisor Free
-------------------------------------------------------------------------------------
CPU 2 12.00 2.00 0.00 - 10.00
Note: As customer suggested in issue, AL 3.7 Release Notes will be updated to reflect this change. Currently Release Notes in Important Notes section contain only this information:
As of 3.7 GA for Xen-based grids, the grid controller is assigned 1 full CPU core for its own exclusive use. CA AppLogic will not assign any appliances to run on the same CPU core as the grid controller). For ESX-based grids, the grid controller still uses 10% of a core (as in all previous releases.
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