1. IIS 6
IIS 6.0 was capable of scaling out to virtually any number of web servers and had tools like
IISCnfg.vbs to keep the IIS metabase in sync between the nodes.
2. IIS 7
IISCnfg.vbs is no longer available with IIS 7.0 but has been replaced with AppCmd.exe and
the new shared configuration.
Shared Configuration
One major improvement that IIS 7.0 brings to the table specifically for web farms: shared configuration.
Shared configuration allows you to store the IIS configuration files in a location of your choosing — either locally or over a UNC path,
where multiple IIS servers can point to the same location without any sharing contention.
The new configuration mechanism does not hold a lock on the files, so multiple servers can work with the same file simultaneously.