Hi Alla,

A quick look tells me that ecmdb_admin is available without installing Discovery. This is your Enterprise CMDB Admin. Modules available to this user include the Dependency Views.

discovery_admin is just what it sounds like - an admin that manages and maintains the discovery configuration. As with any security, only grant the roles required to the job, and not more.

If you don't want someone accidentally fiddling with your Discovery schedules, don't grant them discover_admin role.

http://wiki.servicenow.com/index.php?title=Base_System_Roles