how can I use this result to alert me

In azure logs , I use this to get my linux server disk usage Perf |where TimeGenerated > ago(3min) | where ObjectName == "Logical Disk" // the object name used in Linux records | where Counter...

azure monitor

Query Language

CliveWatson

Jun 16, 2020

JACK_LAI_1117

Perf |where TimeGenerated > ago(3min)
| where ObjectName == "Logical Disk" // the object name used in Linux records
| where CounterName == "% Used Space" and InstanceName != "_Total"
| summarize by InstanceName,CounterValue, bin(TimeGenerated,1m)
| extend AggregatedValue = CounterValue

or see examples on this page:

https://docs.microsoft.com/en-us/azure/azure-monitor/platform/alerts-unified-log