Spotlight is the search system built into Mac OS 10.4 or higher, whenever you make a change to a file spotlight comes along and indexes the metadata of that file. This feature is great it means that you can find stuff really fast. Whenever you attach an external disk to the system Spotlight will index the drive also, this can be very annoying if say for example you have a separate partition with another copy of Mac OS X that you don’t won’t indexed, or it could be a partition containing your backups.

There is a configuration panel in System Preferences for things to exclude from the Spotlight search but drives don’t seem to stick. Under the hood of the OS there are some utils that can help here. one is called mdutil. mdutil which I suppose is named metadatautil really lets you turn Spotlight on/off and lets you delete the metadata store so that it could be rebuilt.

To deactivate Spotlight on a certain drive (in my case my firewire drive called “TinyDrive”) just enter the terminal and do the following.

If you want to reactivate Spotlight use the main command above but changing off to on

Hope this helps