Where is the first part of the index home path defined?

I've sort of took on Splunk administration for my company so I'm trying to make sense of this as quickly as I can. Under Indexes I see you can define a "Home Path" and here is what I currently see: ![alt text][1] [1]: /storage/temp/226692-homepath.png When I place my mouse over the row it displays "/opt/splunkdata/smt_tableau/db" but notice how the Home Path is titled as "volume:summit_ps/smt_tableau/db" in the picture. So I'm guessing there's a place where "volume:summit_ps" is defined to look in /opt/splunkdata but I can't find it anywhere. Sorry if this is confusing.