With SharePoint 2010 RTM looming, I’ve stumbled across an architectural change that may surprise some people – namely, that SharePoint 2010 no longer supports multiple-server farms without a domain infrastructure. In SharePoint 2007 it was possible to create SharePoint farms in a Workgroup, so long as all of the user accounts for the services and application pool identities were named the same and had the same password. You could even manage users with an Active Directory Lightweight Directory Services (AD LDS) or Active Directory Application Mode (ADAM) LDAP directory (albeit with some fairly limiting restrictions). However, it was possible to use these farms for testing or when an Active Directory infrastructure was undesirable (as some people see it in a DMZ). Now, it is still possible to do a Simple installation on a single server without full domain services, but it is no longer supported on multiple servers, and the Simple installation comes with its own planning considerations, to which I’ll return in a bit. First, there’s another wrinkle regarding the single server Complete installation.