Creating a Snapshot Alarm

Creating a Snapshot Alarm

An alarm can be created to display a warning or alert on a virtual machine if a snapshot grows to be larger than a threshold set in an alarm trigger.

To create a VM snapshot alarm for all virtual machines in a vCenter’s inventory select the vCenter Server. In the Manage tab select Alarm Definitions and click Add to start the Alarm Definition wizard. Give the alarm and name and description.

Add a new Trigger and select VM Snapshot Size for the Trigger.

Set the Warning Condition to the snapshot size in GB that should trigger a warning, in this example the size is set to 10 GB. Set the Critical Condition to the snapshot size in GB that should trigger a critical alert, in this example the size is set to 15 GB.

An action can be configure to send an email to an administrator if a warning or critical alarm is triggered.

The new VM Snapshot Size alarm is added to the alarm definitions.

If a snapshot grows to a size larger than what has been configured the alarm is triggered and the warning or alert is displayed on the VM and in the Alarms box in the Web Client.

Source:

False duplicate IP address detected on Microsoft Windows Servers and later virtual machines on ESX/ESXi when using Cisco devices on the environment

False duplicate IP address detected on Microsoft Windows Vista and later virtual machines on ESX/ESXi when using Cisco devices on the environment

Symptoms

When you assign an IP address on Windows Vista and later versions, you see a duplicate IP address conflict.

When you restart Windows Vista and later versions, you receive a 169.254.x.x IP.

When you set up the same virtual machine on a vSwitch with no uplink port on the vSwitch, the IP address is assigned successfully.

When you assign the same IP address to a Windows 2003 virtual machine on the same vSwitch, the IP address is assigned successfully.

Cause

This issue occurs when the Cisco switch has gratuitous ARPs enabled or the ArpProxySvc replied to all ARP requests incorrectly.

Resolution

Note: Investigate the network configuration at the physical layer for the root cause. For more information from Cisco

To work around this issue, turn off gratuitous ARP in the guest operating system.

Note: This procedure modifies the Windows registry. Before making any registry modifications, ensure that you have a current and valid backup of the registry and the virtual machine. For more information on backing up and restoring the registry, see the Microsoft Knowledge Base article 136393.

To turn off gratuitous ARP in the guest operating system:

Shut down the guest operating system and power off the virtual machine.

Change the virtual machine to a network vSwitch with no uplink. You can create one for this procedure.

Power on the virtual machine and log in.

Open the Registry editor.

In Windows XP to Windows Server 2003 - Click Start > Run, type regedit, and click OK.

In Windows 7 and Current - Click Start, type regedit, and click OK.

Locate this registry key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

Click Edit > New, and click DWORD Value.

Type ArpRetryCount.

Right-click the ArpRetryCount registry entry and click Modify.

In the Value box, type 0 and click OK.

Exit the Registry Editor.

1. Shut down the guest operating system and power off the virtual machine.

2. Change the virtual machine back to a network vSwitch with the uplink.

3. Power on the virtual machine.

4. Alternatively, you can disable gratuitous ARP on the physical switch.

For example:

To disable gratuitous ARP in Cisco IOS, run this command:

# no ip gratuitous-arps