Spotlight indexing is automatically disabled in Mac OS X Server and automatically enabled in Mac OS X. The mdutil command can be used to enable/disable indexing per volume. To enable indexing on a volume you would use the -i option followed by on and then the volume name. For example, if you wanted to enable Spotlight indexing for a volume called bighonkinvolume you would use the following command:
mdutil -i on bighonkinvolume
Whereas to then disable Spotlight indexing on that same volume you would use the -i option again followed by off this time. For example:
mdutil -i off bighonkinvolume
Alternatively, there is a GUI tool called Spotless that provides even more granularity and a bit more of a sleek interface than doing so in the terminal.
