List one of the occasion when you would like to isolate vCenter instance from linked mode group?
When vCenter instance domain needs to change, you’ve to first isolate it from linked mode group. Change the domain and make sure SDK and Webservices URL are matching hostname and domain name and Rejoin it to linked mode group.
Is it necessary to login using domain account to search object in vCenter when in linked mode?
yes it is absolutely necessary to login using domain account, as your credentials and it’s permissions are checked against AD. In linked mode it makes more sense to login using domain account. If you login using local account you can only search object in local instance. Also To be noted is you can only view & search objects for which you have permission.
What is the most important policy rules for task operations?
In order to create Task you must have necessary permissions on the object. Once the task is create, it continues to run as per schedule even if user who creates the task no longer has permissions on the object.
How are virtual machine version compatible with earlier version?
Virtual Machine created on esx4.0 cannot be run on earlier esx version. In esx4.0 Virtual machine hardware version is 7.0
virtual Machine created on esx3.x can be run on esx4.0, it can also be edit. you can also create virtual machine compatible with esx3.x on esx4.0. while creating virtual machine just select virtual machine hardware version4.0.
Virtual machine created on esx2.x hardware can also run on esx4.0 but it cannot modify it