ESX host settings for environments with up to 80 virtual machines per host in a VMware HA cluster
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ESX host settings for environments with up to 80 virtual machines per host in a VMware HA cluster

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Article ID: 343090

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Updated On:

Products

VMware vCenter Server VMware vSphere ESXi

Issue/Introduction

Starting with VirtualCenter 2.5 Update 5, an ESX host in an VMware High Availability (HA) cluster can support up to 80 virtual machines. For all virtual machines to power on on other hosts in the cluster if hosts within the failover capacity limit fail, you must ensure that these parameters in the ESX hosts are set with these values:
ParameterValueApplicability
Misc.RunningVCpuLimit192vCPUESX Server 3.5 and ESX Server 3i Embedded
Service console memory512MBESX Server 3.5
vim resource pool memory reservation1024MBESX Server 3i Embedded
Host agent memory configuration
<hostdStopMemInMB>380</hostdStopMemInMB>
<hostdWarnMemInMB>300</hostdWarnMemInMB>
ESX Server 3.5 and ESX Server 3i Embedded


Environment

VMware ESXi 3.5.x Embedded
VMware VirtualCenter 2.5.x
VMware ESX Server 3.5.x

Resolution

ESX 3.5 Hosts

To enable ESX 3.5 hosts to support up to 80 virtual machines in an HA cluster:
  1. Increase the maximum vCPU limit to 192:
    1. In VMware Infrastructure (VI) Client, select the ESX host.
    2. Click the Configuration tab and select Advanced Settings.
    3. In the Advanced Settings window, select the Misc menu, and change Misc.RunningVCpuLimit to 192.

  2. Include or edit the host agent memory configuration values:
    1. Login to the ESX host as user root using an SSH client.
    2. Make a backup copy of the host agent configuration file /etc/vmware/hostd/config.xml. This backup copy can be placed in the / directory.
    3. Edit the /etc/vmware/hostd/config.xml file.
    4. Within the <config> and </config> tags, include or edit these values:

      <hostdStopMemInMB>380</hostdStopMemInMB>
      <hostdWarnMemInMB>300</hostdWarnMemInMB>


    5. Save the file and exit.

      Note
      : For the new values to take effect immediately, restart the ESX Server Management service. For more information, see Restarting the Management agents on an ESX or ESXi Server (1003490). If you are going to change the Service Console memory value as described in the next step, rebooting the ESX Server host restarts the ESX Server Management service.

  3. Increase the Service Console memory value to 512 MB:
    1. In VI Client, select the ESX host.
    2. Click the Configuration tab and select Memory.
    3. Click Properties, and in the Memory window, change the value for Service Console to 512.
    4. Reboot the ESX host for the new value to take effect. For more information, see Increasing the amount of RAM assigned to the ESX Server service console (1003501) and Rebooting an ESX Server host (1003530)

ESXi 3 Embedded Hosts

To enable ESXi 3i Embedded hosts to support up to 80 virtual machines in an HA cluster:
  1. Increase the maximum vCPU limit to 192:
    1. In VI Client, select the ESXi host.
    2. Click the Configuration tab and select Advanced Settings.
    3. In the Advanced Settings window, select the Misc menu, and change Misc.RunningVCpuLimit to 192.

  2. Increase the memory resource reservation of the vim resource pool to 1024 MB:
    1. In VI Client, select the ESXi host.
    2. Click the Configuration tab and select System Resource Allocation.
    3. Click Advanced, and select vim from the System Resource Pools list.
    4. Click Edit Settings.
    5. In the Edit vim Resource Allocation window, change the value for Memory Resources Reservation to 1024.

  3. Include or edit the host agent memory configuration values:
    1. Login to the ESXi host using Tech Support Mode as detailed in Tech Support Mode for Emergency Support (1003677)
    2. Make a backup copy of the host agent configuration file /etc/vmware/hostd/config.xml. This backup copy can be placed in the / directory.
    3. Edit /etc/vmware/hostd/config.xml file.
    4. Within the <config> and </config> tags, include/edit these values:

      <hostdStopMemInMB>380</hostdStopMemInMB>
      <hostdWarnMemInMB>300</hostdWarnMemInMB>


    5. Save the file and exit.
    6. Exit Tech Support Mode
    7. For the changes to take effect, restart the Management Agents on ESXi 3 as described in Restarting the Management agents on an ESX or ESXi Server (1003490)
Note: The Maximum number of hosts per HA cluster is 32 as per the Configuration Maximums for VMware Infrastructure 3 guide.