Or we can try rape that chart:
1) add "Custom Chart" resource into Report
2) as data source use Advanced DataBase Query (SQL, SWQL)
3) Check "SQL" query type
4) Use following query:
SELECT N.MachineType, DD.Date, SUM (CASE WHEN Mult = 0 THEN -1 ELSE 1 END) AS Count
FROM Nodes N
-- ${ToTime} - bug has to be there
cross join (
SELECT DATEADD(mi,-30, GETDATE()) AS Date, 0 as Mult
UNION all
SELECT GETDATE() AS Date, 1 as Mult
UNION ALL
SELECT DATEADD(mi,30, GETDATE()) AS Date, 0 as Mult
) AS DD
GROUP BY MachineType, DD.Date, DD.Mult
ORDER BY DD.Date
5) Go to Edit chat page
6) Set chart type: Column
7) Add data series, Select "Count" field, and set "Date" field as Time column, see picture.
8) Select "MachineType" field in option: "Object ID column"
9) Sample interval set to 30 minutes.
