We are in the process of moving our Sharepoint VM instance from one DC to the other.But i would like to have some backup before the move. They are requesting to clone the server. Anyways whats the difference between a SharePoint Farm or Site Collection in terms of restoring the instance back. Which one of them would give me a full restore? Thanks in Advance
well obviously you would want a farm backup! it will contain all sitecollections within the farm.
The sharepoint farm is everything from the server down, including the webapplication to top level sites and its subsites(site collection) in sharepoint terms its SPSite.
A better understanding you can find it here:
As you can see a site collection would be from one webapplication but on the farm you can have many webapplications and under them many site collections.
Cloning your server is a better option on a VM.
also this for cloning:
as for just a site collection you can just use the stsadm or powershell tool :)
For a full restore I would go with farm :) if your looking to resore all webapplications that contain all site collections and their subsites!
Hope this is enough info for you :)