If a production webserver with several sites has been set up as per the defaults, then websites will be created under C:\INETPUB, and log files will be written to C:\System32\LogFiles.
This has implications for disk space on C:as sites grow and logging increases. The size of that partition is not easily increased (without third party tools like Acronis Disk Director), and a better configuration is to move websites and logfiles to their own volume.
How do you migrate IIS to a new partition?
Is it better to simply xcopy each site, then reconfigure each site to point to the new files? New sites would still be be created on C:\INETPUB unless the webmaster remembered to change the default. And what about virtual folders, maybe buried deep and easily missed?
Or can IIS be moved all at once, maintaining the relative structure, but swapping out C: for D:\ wherever it appears?
Moving large sub-directories Another idea might be to redirect some large sub-directory (e.g. an uploads folder) to another parttion using virtual directories.