Modifying CPU reservations for hardware with lower CPU speeds

Last Updated : May 14, 2025 |
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Avaya provides the minimum resource requirements to support different profiles for Communication Manager in table. If a customer’s VMware infrastructure contains servers that do not meet the minimum required CPU speed per footprint as mentioned in the table, the Communication Manager VM will not be able to start after deployment. A customer may choose to modify the CPU reservations to allow the Communication Manager VM to start.
However, this may have an impact on performance of the Communication Manager and will not be supported if an escalation to Avaya is determined to be the result of an unsupported/tested CPU speed. Avaya may request that the Communication Manager be deployed on a supported platform with the required/documented reservations.
If a customer acknowledges the above, and chooses to move forward with deployment on a server with a CPU speed less than the required minimum, the following steps would be utilized.
  1. Login to the ESXi embedded host client.
  2. In the left Navigator pane, select Host.
  3. In the Hardware display, identify the CPU settings of the host.
    ADDITIONAL INFORMATION:
    For example: 20 CPUs x Intel(R) Xeon(R) Silver 4114 CPU @ 2.20GHz.
    Alternatively, Under CPUProcessor Type, shows similar information such as Intel(R) Xeon(R) Silver 4114 CPU @ 2.20GHz.
    Note:
    In this example, the CPU speed is 2.20 GHz (2200 MHz)
  4. In the left Navigator pane, select Virtual Machines.
  5. Right-click the required VM and select Edit settings.
    ADDITIONAL INFORMATION:
    The Virtual Hardware tab is displayed.
  6. In the left pane of the Virtual Hardware tab, do the following:
    1. Expand the CPU entry.
    2. Modify the reservation entry to allow the VM to start.
    3. Save the changes.
    4. Power on the VM.
    ADDITIONAL INFORMATION:
    The following rules should be used to determine how to modify the reservation entry.
    ADDITIONAL INFORMATION:
    For Duplex Communication Manager VMs: Modify the reservation to 3 times the CPU speed of the server (determined from step 3). Example: If the CPU speed of the server is 2200MHz, modify the reservation for Communication Manager High Duplex Max (41K users) from 7650 to 3 * 2200 = 6600.
    For Simplex Communication Manager VMs: Do not modify the Communication Manager Main Max users 1000, and the Communication Manager Survivable Max users 1000.
    For Communication Manager Simplex Max users 2400 and for Communication Manager Simplex Max users 41K, modify the reservation to 2 times the CPU speed of the server (determined from step 3).
    For example, if the CPU speed of the server is 2000MHz, modify the reservation for Communication Manager Simplex Max (41K users) from 4340 to 2 * 2000 = 4000.
    ADDITIONAL INFORMATION:
    Important:
    Do NOT change any other resource settings, for example, removing resources completely. Modifying these allocated resources can have a direct impact on the performance and capacity of the Communication Manager virtual machine. Virtual machine must meet the resource size requirements so that Communication Managercan run at full capacity. Removing or greatly downsizing resource reservations can put this requirement at risk. You are responsible for making any modifications to the resource reservation settings and acknowledge the potential performance impacts of running on a host that is less than the minimum required CPU speed.
    ADDITIONAL INFORMATION:
    Warning:
    If a virtual machine problem occurs, Avaya Global Support Services (GSS) might not be able to assist in fully resolving a problem. Avaya GSS can help you to reset the values to the optimized values before starting to investigate the problem. Depending on the outcome of the investigation, it is possible you will be required to deploy on a host with the minimum required CPU speed/reservation.