This function retrieves the disk space that an email account uses.
Important:
When you disable the Receive Mail role, the system disables this function.
uapi --output=jsonpretty \ --user=username \ Email \ get_disk_usage \ user='user' \ domain='example.com'
{- "apiversion": 3,
 - "func": "get_disk_usage",
 - "module": "Email",
 - "result": {
- "data": {
- "diskused": 399.6,
 - "domain": "example.com",
 - "login": "user@example.com",
 - "user": "user"
 
}, - "errors": null,
 - "messages": null,
 - "metadata": { },
 - "status": 1,
 - "warnings": null
 
} 
}