Unable to get memory Utilization in monitoring

Question

Unable to get memory Utilization in monitoring

Harikiran B S 45

I have a FortiGate HA with ELB VM NVA deployed in azure but unable to get memory metrics it shows as 0, but able to get network in & out and cpu utilization.

Is there any article in MS which states Forti OS is not supported for monitoring resource utlization like memory, cpu and network

Pranitha Sika 0 Reputation points Microsoft External Staff Moderator

2026-07-20T15:10:21.2766667+00:00
Hello Harikiran B S

FortiGate HA VM with ELB (NVA) deployed in Azure is unable to retrieve Memory Utilization metrics, while CPU Utilization, Network In, and Network Out metrics are available.

If the FortiGate HA VM in Azure displays CPU Utilization, Network In, and Network Out metrics, but Memory Utilization is shown as 0, this does not necessarily indicate that FortiOS is unsupported. Guest OS memory metrics are not collected automatically by Azure Monitor and require appropriate guest-level monitoring configuration.

Possible Causes

Azure Monitor Agent (AMA) not installed

Guest OS metrics, including memory utilization, require Azure Monitor Agent (AMA) to be installed and configured properly.

Guest metrics collection not configured

Even when AMA is installed, guest performance counters such as memory utilization must be configured for collection through the monitoring configuration.

Correct metrics namespace not selected

Verify that the appropriate guest metrics namespace is selected in Azure Monitor:

azure.vm.windows.guest

azure.vm.linux.guest

Select the relevant memory metric, such as Committed Bytes in Use.

Storage account firewall blocking diagnostics ingestion

If diagnostic data collection is restricted by storage account firewall or networking rules, metrics may not be ingested successfully and could appear as missing or zero.

Legacy monitoring agents or extensions

Legacy Azure Diagnostics extensions or deprecated Log Analytics agents may result in incomplete guest OS metric collection.

Microsoft recommends using Azure Monitor Agent (AMA) for guest OS monitoring scenarios.

Recommended Validation Steps

VM Insights installs and configures AMA automatically

Enabling VM Insights deploys and configures Azure Monitor Agent (AMA) and applies the default guest monitoring configuration. This is the recommended approach for collecting guest OS performance metrics.

Check Diagnostic Settings on the VM

Navigate to:

VM → Monitoring → Diagnostic Settings

Verify that Guest OS metrics collection is configured, including memory-related counters.

Verify Azure Metrics Explorer

Navigate to:

Azure Monitor → Metrics

Select the affected VM.

Verify the appropriate metrics namespace:

azure.vm.windows.guest

azure.vm.linux.guest

Select a memory-related metric such as Committed Bytes in Use and confirm whether data is available.

Check storage account and network restrictions

Ensure that storage account, firewall, or network policies are not blocking diagnostics data ingestion.

Review monitoring agent configuration

If older monitoring agents or extensions are in use, migrate to Azure Monitor Agent (AMA), as legacy agents are deprecated for guest OS monitoring scenarios.

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Answer 1

That pattern is expected for an Azure VM/NVA. Azure supplies host-level CPU, network, and disk metrics automatically, but guest memory is not a platform metric. It must be collected inside the guest, so zero does not mean FortiGate is using no memory.

For supported Windows or Linux VMs, enable VM insights or Azure Monitor Agent with a data collection rule for guest performance counters. FortiOS is not listed among the operating systems supported by Azure Monitor Agent, so Microsoft’s standard guest-memory collection path is not supported for this appliance image.

Check the FortiGate offer or publisher guidance for a supported way to export memory telemetry. If available, ingest that data into an Azure Monitor destination and query and alert on it instead of the VM platform metric. CPU and network remain visible because Azure measures them at the host. Without that path, Azure Monitor cannot collect guest memory.