I am trying to setup a alert when the free space falls below 5% of its capacity.
I have written the below Kusto query as following.
Perf
| where CounterName == "% Free Space"
| where Computer == "VM-01"
| where InstanceName == "C:"
| where InstanceName != "_Total" and InstanceName !contains "HarddiskVolume"
| summarize arg_max(TimeGenerated, *) by InstanceName
| project CounterValue
The query provides desired output while executing on the Log Analytics Workspace.

When I use the same query on the Alert page, I get the preview output as 1 and the alert gets triggered even if the free space is a threshold value of 5%.

Can anyone let me know where am I going wrong and point me in to correct direction?
Thanks in advance for helping me out.
Regards, Ronak.
