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Arslan11's avatar
Arslan11
Brass Contributor
Apr 30, 2020

Report on selected servers for a week on the memory usage

I would like a help with a Kusto  query which I have almost completed but I am struggling in the last part.   Kusto query Perf | where ObjectName == "Memory" and CounterName == "% Committed Bytes...
Azure Log Analytics
azure monitor
CliveWatson's avatar
CliveWatson
Former Employee
May 07, 2020

SamsonJohn 

 

Two questions,

 

1. what is perf collection interval for the memory counter?  My thoughts are if you are collecting to a different interval to Perfmon you may see variation based in aggregation.

2. Are you using Perfmon (the counters and data is the same, apart from the collection interval); Task Manager can show different results.

 

 

Go to Log Analytics and run query

Perf
| where TimeGenerated > ago(1h)
| where Computer == "retailEUS7"
| where ObjectName == "Memory" and CounterName == "% Committed Bytes In Use"
| summarize maxUsed_Percent_Memory = max(CounterValue),
avgUsed_Percent_Memory = avg(CounterValue)
by bin(TimeGenerated,1m) , Computer
| project-away Computer
| render timechart

 

I think it unlikely Avg is the same as Max. See this example:

 

 

 

SamsonJohn's avatar
SamsonJohn
Copper Contributor
May 07, 2020

CliveWatson

Sure to Answer the question please find below 

1) Perfmon Set is as below 

 

2) After executing the query

So both are coming same  avg and max, there is no change .

 

Please let me know if you have any updates in regards to the same.

 

  • CliveWatson's avatar
    CliveWatson
    Former Employee
    May 13, 2020

    SamsonJohn 

     

    Log Analytics stores the same data as Perfmon, do the Perfmon charts match your Log Analytics query?  That's the apples to apples comparison.  Now I'm in no way saying this is the issue, but Task Manger could be showing a different view, one example https://sqlinthewild.co.za/index.php/2016/01/19/stop-using-task-manager-to-check-sqls-memory-usage/. 

    I can only help you compare Perfmon with Log Analytics - are these different for the same time period?  

  • SamsonJohn's avatar
    SamsonJohn
    Copper Contributor
    May 12, 2020

    CliveWatson 

    Yes even after doing those changes I am seeing the difference .

     

    And the Actual Memory Utilization is as below

    So In actual the query is returning the memory committed percent the actual utilized memory (in the above image is 77 percent)

     

    I feel we need to change the query for the actual percent.

     

     

     

     

  • CliveWatson's avatar
    CliveWatson
    Former Employee
    May 10, 2020

    SamsonJohn 

     

    Ok, so you avg and max are the same (some workloads can be).  Have you setup Perfmon to match your settings, something like?

    Are you still seeing a ~10% difference?

     

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