Roles are a group of permissions: create a "Read Only" role.

Here is a good knowlege artical on creating a "Read Olny" role.

Goal

There may be requirement where you don't want to give all administrative rights to a user and just want to give specific permission.
This can be achieved using roles.

But there may be situations where you want a user to give just Read Only permissions.
In other words you may wish wish a user to just monitor and check the status but should not be able to modify anything.

Here is a link to the KM 1541562.1

Sun Storage 7000 Unified Storage System: Unable to create a "Read Only" role.