Azure Metric vs Performance counters show different values

[Mali_Stane]

Azure Metric vs Performance counters

Return values of network traffic are totally off, regardless of time frame between portal, log analytic query perf and InsightsMetrics. See screen off excel.

I have open log analytic workspace, select Time range Last 24 hours and one day 26/03/2024
Perf

| where TimeGenerated between (datetime(2024-03-26) .. datetime(2024-03-27))
| where Computer == "**********"
| where ObjectName == "Network Interface" and CounterName == "Bytes Sent/sec" or CounterName == "Bytes Received/sec"
| summarize BytsSent = sum(CounterValue) by bin(TimeGenerated, 1d),CounterName

InsightsMetrics
| where TimeGenerated between (datetime(2024-03-26) .. datetime(2024-03-27))
| where Origin == "vm.azm.ms"
| where Computer == "*******"
| where Namespace == "Network"
| where Name == "ReadBytesPerSecond" or Name == "WriteBytesPerSecond"
| extend Tags = parse_json(Tags)
| extend BytestoSec = toreal(Tags.["vm.azm.ms/bytes"])
| sort by TimeGenerated
| project TimeGenerated,Name,Val,BytestoSec
| summarize AggregatedValue = sum(BytestoSec) by bin(TimeGenerated, 1d),Name

I don’t know what im doing wrong or i don't understand . But sample interval in data collection rule is  15s, and  sample interval of metric is 60s.

[#2]

I've run into something similar in the past. My understanding is that performance counters return data from the OS perspective whereas metrics are how Azure sees usage from a host perspective. I would rely on the performance counter data in Log Analytics over metric data.

[#3]

Correctly.
According to the tests and metrics collected on the network infrastucture is log analytic value is more exact/ identical to what ststistic is provide. Azure metric is more or less general information, how system behave that is in my opinion.