A couple of weeks back, I wrote about using Microsoft’s system preparation tool (SysPrep) to prepare virtual machine images for duplication. It doesn’t really matter whether the machine is virtual or physical, the principle is still the same (my point was that cloning virtual machines using a file copy is easy but needs to be prepared in a specific way – i.e. using SysPrep).

A few days ago I was completely amazed to hear how one of my clients had duplicated some of their servers – they had simply broken a mirror, placed the second disk in a new server, then added another disk in each server to recreate the mirror (repeat until all servers are successfully duplicated). It may be ingenious, but it’s also extremely bad practice.

The client in question is in the process of preparing for a migration from Windows NT to Windows Server 2003 and Active Directory. Although NT doesn’t get too upset if servers are cloned, including their security identifier (SID), Active Directory does. They now have three choices:

• Rebuild the problem servers.
• Remove the servers from the domain.
• Use a tool like Sysinternals NewSID to change the SIDs (both officially unsupported by Microsoft).

Whatever the decision, it’s all extra (and unnecessary) work – completely avoidable.