You can use the system-generated roles such as Data Controller or Compliance, or you can add the permissions to user-defined roles.
Risk Analysis - File Storage Optimization and Sensitive Data Governance
| 
 User roles  | 
 Permissions  | 
 Associated CommCell entities  | 
|---|---|---|
  | 
  | 
 CommCell or Company (Tenant)  | 
| 
 Data Processor (reviewer)  | 
 No permissions are needed  | 
eDiscovery and Compliance
| 
 User roles  | 
 Permissions  | 
 Associated CommCell entities  | 
|---|---|---|
| 
 Case Manager User  | 
  | 
 Exchange user mailbox, Journal mailbox, or SMTP clients where the custodian data is backed up  | 
| 
 Case Manager Reviewer  | 
  | 
 Exchange user mailbox, Journal mailbox, or SMTP clients where the custodian data is backed up  | 
| 
 Compliance Officers  | 
  | 
 Servers or server groups  |