Hello,
If you go into OnBase Configuration | Disk Mgmt | Disk Groups > Select the Disk Group you would like to view the information for. You can then click on Volume Information | Read-Only Mode > Then you will click on the Volume you want the path for. You will notice the platter path is populated (Depending on how many copies were configured), and you can copy/paste the path into a Windows Explorer window to search for that path. If you have access to the specified path, you can use the "\\'network-location'\'folder-name'\'database-name(possibly used if they have it specified to the database)" folder location to create a new "Disk Group", name the folder whatever you would like, and remember the path to add that when configuring the new disk group.
