title	Monitoring data reference for Azure Load Balancer
description	This article contains important reference material you need when you monitor Azure Load Balancer by using Azure Monitor.
ms.date	08/21/2024
ms.custom	horz-monitor
ms.topic	reference
author	mbender-ms
ms.author	mbender
ms.service	azure-load-balancer

Azure Load Balancer monitoring data reference

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See Monitor Azure Load Balancer for details on the data you can collect for Load Balancer and how to use it.

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Supported metrics for Microsoft.Network/loadBalancers

The following table lists the metrics available for the Microsoft.Network/loadBalancers resource type.

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Metric	Name in REST API	Unit	Aggregation	Dimensions	Time Grains	DS Export
Allocated SNAT Ports Total number of SNAT ports allocated within time period	`AllocatedSnatPorts`	Count	Average	`FrontendIPAddress`, `BackendIPAddress`, `ProtocolType`	PT1M	No
Byte Count Total number of Bytes transmitted within time period	`ByteCount`	Bytes	Total	`FrontendIPAddress`, `FrontendPort`, `Direction`	PT1M	Yes
Health Probe Status Average Load Balancer health probe status per time duration	`DipAvailability`	Count	Average	`ProtocolType`, `BackendPort`, `FrontendIPAddress`, `FrontendPort`, `BackendIPAddress`	PT1M	Yes
Health Probe Status Azure Cross-region Load Balancer backend health and status per time duration	`GlobalBackendAvailability`	Count	Average	`FrontendIPAddress`, `FrontendPort`, `BackendIPAddress`, `ProtocolType`	PT1M	Yes
Packet Count Total number of Packets transmitted within time period	`PacketCount`	Count	Total	`FrontendIPAddress`, `FrontendPort`, `Direction`	PT1M	Yes
SNAT Connection Count Total number of new SNAT connections created within time period	`SnatConnectionCount`	Count	Total	`FrontendIPAddress`, `BackendIPAddress`, `ConnectionState`	PT1M	Yes
SYN Count Total number of SYN Packets transmitted within time period	`SYNCount`	Count	Total	`FrontendIPAddress`, `FrontendPort`, `Direction`	PT1M	Yes
Used SNAT Ports Total number of SNAT ports used within time period	`UsedSnatPorts`	Count	Average	`FrontendIPAddress`, `BackendIPAddress`, `ProtocolType`	PT1M	No
Data Path Availability Average Load Balancer data path availability per time duration	`VipAvailability`	Count	Average	`FrontendIPAddress`, `FrontendPort`	PT1M	Yes

Load balancer metrics

This table includes additional information about metrics from the Microsoft.Network/loadBalancers table:

Metric	Resource type	Description
Allocated SNAT ports	Public load balancer	Standard Load Balancer reports the number of SNAT ports allocated per backend instance.
Byte count	Public and internal load balancer	Standard Load Balancer reports the data processed per front end. You might notice that the bytes aren't distributed equally across the backend instances. This behavior is expected as Azure's Load Balancer algorithm is based on flows.
Health probe status	Public and internal load balancer	Standard Load Balancer uses a distributed health-probing service that monitors your application endpoint's health according to your configuration settings. This metric provides an aggregate or per-endpoint filtered view of each instance endpoint in the load balancer pool. You can see how Load Balancer views the health of your application, as indicated by your health probe configuration.
SNAT connection count	Public load balancer	Standard Load Balancer reports the number of outbound flows that are masqueraded to the Public IP address front end. Source network address translation (SNAT) ports are an exhaustible resource. This metric can give an indication of how heavily your application is relying on SNAT for outbound originated flows. Counters for successful and failed outbound SNAT flows are reported and can be used to troubleshoot and understand the health of your outbound flows.
SYN count (synchronize)	Public and internal load balancer	Standard Load Balancer doesn’t terminate Transmission Control Protocol (TCP) connections or interact with TCP or User Data-gram Packet (UDP) flows. Flows and their handshakes are always between the source and the virtual machine instance. To better troubleshoot your TCP protocol scenarios, you can make use of SYN packets counters to understand how many TCP connection attempts are made. The metric reports the number of TCP SYN packets that were received.
Used SNAT ports	Public load balancer	Standard Load Balancer reports the number of SNAT ports that are utilized per backend instance.
Data path availability	Public and internal load balancer	Standard Load Balancer continuously exercises the data path from within a region to the load balancer front end, all the way to the SDN stack that supports your virtual machine. As long as healthy instances remain, the measurement follows the same path as your application's load-balanced traffic. The data path that your customer's use is also validated. The measurement is invisible to your application and doesn't interfere with other operations.

Note

Data Path Availability metric may take up to 10 minutes to appear in Azure Monitor metrics after a load balancer is created or updated.

Global load balancer metrics

This table includes additional information about global metrics from the Microsoft.Network/loadBalancers table:

Metric	Resource type	Description
Health probe status	Public global load balancer	Global load balancer uses a distributed health-probing service that monitors your application endpoint's health according to your configuration settings. This metric provides an aggregate or per-endpoint filtered view of each instance regional load balancer in the global load balancer's backend pool. You can see how global load balancer views the health of your application, as indicated by your health probe configuration.
Data path availability	Public global load balancer	Global load balancer continuously exercises the data path from within a region to the load balancer front end, all the way to the SDN stack that supports your virtual machine. As long as healthy instances remain, the measurement follows the same path as your application's load-balanced traffic. The data path that your customer's use is also validated. The measurement is invisible to your application and doesn't interfere with other operations.

Note

Bandwidth-related metrics such as SYN packet, byte count, and packet count doesn't capture any traffic to an internal load balancer by using a UDR, such as from an NVA or firewall.

Max and min aggregations are not available for the SYN count, packet count, SNAT connection count, and byte count metrics. Count aggregation is not recommended for Data path availability and health probe status. Use average instead for best represented health data.

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Dimension	Name	Description
BackendIPAddress	Backend IP	The backend IP address of one or more relevant load balancing rules
BackendPort	Backend Port	The backend port of one or more relevant load balancing rules
ConnectionState	Connection state	The state of SNAT connection. The state can be pending, successful, or failed
Direction	Direction	The direction traffic is flowing. This value can be inbound or outbound.
FrontendIPAddress	Frontend IP	The frontend IP address of one or more relevant load balancing rules
FrontendPort	Frontend Port	The frontend port of one or more relevant load balancing rules
ProtocolType	Protocol Type	The protocol of the relevant load balancing rule. The protocol can be TCP or UDP