There is a problem with the with HA in VMware ESX 3.5 Update 3. Virtual Machines may reboot unexpectedly when migrated with VMotion or after a Power On operation. This is only when the Virtual Machine is running on an ESX 3.5 Update 3 Host and the ESX Host has VMware HA enabled with "Virtual Machine Monitoring" option active.To work around this problem:
Option 1: Disable Virtual Machine Monitoring
1. Select the VMware HA cluster and choose Edit Settings from the right-click menu.
2. In the Cluster Settings dialog box, select VMware HA in the left column.
3. Un-Check the Enable virtual machine monitoring check box.
4. Click OK.
Option 2: Set hostd hearbeat delay to 0
1. Disconnect the host from VC (Right click on host in VI Client and select "Disconnect" )
2. Login as root to the ESX Server with SSH.
3. Using a text editor such as nano or vi, edit the file /etc/vmware/hostd/config.xml
4. Set the "heartbeatDelayInSecs" tag under "vmsvc" to 0 seconds as shown here:
5. Restart the management agents for this change to take effect.
service mgmt-vmware restart
6. Reconnect the host in VC ( Right click on host in VI Client and select "Connect" )