Merge pull request #246752 from EdB-MSFT/patch-13

Update metrics-troubleshoot.md

Author: Jill Grant

articles/azure-monitor/essentials/metrics-troubleshoot.md

@@ -5,32 +5,32 @@ author: vgorbenko
 services: azure-monitor
 ms.reviewer: vitalyg
 ms.topic: troubleshooting
-ms.date: 06/09/2022
+ms.date: 09/27/2022
 ---
 
 # Troubleshooting metrics charts
 
-Use this article if you run into issues with creating, customizing, or interpreting charts in Azure metrics explorer. If you are new to metrics, learn about [getting started with metrics explorer](metrics-getting-started.md) and [advanced features of metrics explorer](../essentials/metrics-charts.md). You can also see [examples](../essentials/metric-chart-samples.md) of the configured metric charts.
+Use this article if you run into issues with creating, customizing, or interpreting charts in Azure metrics explorer. If you're new to metrics, learn about [getting started with metrics explorer](metrics-getting-started.md) and [advanced features of metrics explorer](../essentials/metrics-charts.md). You can also see [examples](../essentials/metric-chart-samples.md) of the configured metric charts.
 
 ## Chart shows no data
 
 Sometimes the charts might show no data after selecting correct resources and metrics. This behavior can be caused by several of the following reasons:
 
 ### Microsoft.Insights resource provider isn't registered for your subscription
 
-Exploring metrics requires *Microsoft.Insights* resource provider registered in your subscription. In many cases, it is registered automatically (that is, after you configure an alert rule, customize diagnostic settings for any resource, or configure an autoscale rule). If the Microsoft.Insights resource provider is not registered, you must manually register it by  following steps described in [Azure resource providers and types](../../azure-resource-manager/management/resource-providers-and-types.md).
+Exploring metrics requires *Microsoft.Insights* resource provider registered in your subscription. In many cases, it's registered automatically (that is, after you configure an alert rule, customize diagnostic settings for any resource, or configure an autoscale rule). If the Microsoft.Insights resource provider isn't registered, you must manually register it by  following steps described in [Azure resource providers and types](../../azure-resource-manager/management/resource-providers-and-types.md).
 
 **Solution:** Open **Subscriptions**, **Resource providers** tab, and verify that *Microsoft.Insights* is registered for your subscription.
 
 ### You don't have sufficient access rights to your resource
 
 In Azure, access to metrics is controlled by [Azure role-based access control (Azure RBAC)](../../role-based-access-control/overview.md). You must be a member of [monitoring reader](../../role-based-access-control/built-in-roles.md#monitoring-reader), [monitoring contributor](../../role-based-access-control/built-in-roles.md#monitoring-contributor), or [contributor](../../role-based-access-control/built-in-roles.md#contributor) to explore metrics for any resource.
 
-**Solution:** Ensure that you have sufficient permissions for the resource from which you are exploring metrics.
+**Solution:** Ensure that you have sufficient permissions for the resource from which you're exploring metrics.
 
 ### Your resource didn't emit metrics during the selected time range
 
-Some resources don’t constantly emit their metrics. For example, Azure will not collect metrics for stopped virtual machines. Other resources might emit their metrics only when some condition occurs. For example, a metric showing processing time of a transaction requires at least one transaction. If there were no transactions in the selected time range, the chart will naturally be empty. Additionally, while most of the metrics in Azure are collected every minute, there are some that are collected less frequently. See the metric documentation to get more details about the metric that you are trying to explore.
+Some resources don’t constantly emit their metrics. For example, Azure won't collect metrics for stopped virtual machines. Other resources might emit their metrics only when some condition occurs. For example, a metric showing processing time of a transaction requires at least one transaction. If there were no transactions in the selected time range, the chart will naturally be empty. Additionally, while most of the metrics in Azure are collected every minute, there are some that are collected less frequently. See the metric documentation to get more details about the metric that you're trying to explore.
 
 **Solution:** Change the time of the chart to a wider range. You may start from “Last 30 days” using a larger time granularity (or relying on the “Automatic time granularity” option).
 
@@ -46,11 +46,11 @@ By [locking the boundaries of chart y-axis](../essentials/metrics-charts.md#lock
 
 **Solution:** Verify that the y-axis boundaries of the chart aren’t locked outside of the range of the metric values. If the y-axis boundaries are locked, you may want to temporarily reset them to ensure that the metric values don’t fall outside of the chart range. Locking the y-axis range isn’t recommended with automatic granularity for the charts with **sum**, **min**, and **max** aggregation because their values will change with granularity by resizing browser window or going from one screen resolution to another. Switching granularity may leave the display area of your chart empty.
 
-### You are looking at a Guest (classic) metric but didn’t enable Azure Diagnostic Extension
+### You're looking at a Guest (classic) metric but didn’t enable Azure Diagnostic Extension
 
 Collection of **Guest (classic)** metrics requires configuring the Azure Diagnostics Extension or enabling it using the **Diagnostic Settings** panel for your resource.
 
-**Solution:** If Azure Diagnostics Extension is enabled but you are still unable to see your metrics, follow steps outlined in [Azure Diagnostics Extension troubleshooting guide](../agents/diagnostics-extension-troubleshooting.md#metric-data-doesnt-appear-in-the-azure-portal). See also the troubleshooting steps for [Cannot pick Guest (classic) namespace and metrics](#cannot-pick-guest-namespace-and-metrics)
+**Solution:** If Azure Diagnostics Extension is enabled but you're still unable to see your metrics, follow steps outlined in [Azure Diagnostics Extension troubleshooting guide](../agents/diagnostics-extension-troubleshooting.md#metric-data-doesnt-appear-in-the-azure-portal). See also the troubleshooting steps for [Cannot pick Guest (classic) namespace and metrics](#cannot-pick-guest-namespace-and-metrics)
 
 ### Chart is segmented by a property that the metric doesn't define
 
@@ -66,16 +66,16 @@ Filters apply to all of the charts on the pane. If you set a filter on another c
 
 ## “Error retrieving data” message on dashboard
 
-This problem may happen when your dashboard was created with a metric that was later deprecated and removed from Azure. To verify that it is the case, open the **Metrics** tab of your resource, and check the available metrics in the metric picker. If the metric is not shown, the metric has been removed from Azure. Usually, when a metric is deprecated, there is a better new metric that provides with a similar perspective on the resource health.
+This problem may happen when your dashboard was created with a metric that was later deprecated and removed from Azure. To verify that it's the case, open the **Metrics** tab of your resource, and check the available metrics in the metric picker. If the metric isn't shown, the metric has been removed from Azure. Usually, when a metric is deprecated, there's a better new metric that provides with a similar perspective on the resource health.
 
 **Solution:** Update the failing tile by picking an alternative metric for your chart on dashboard. You can [review a list of available metrics for Azure services](./metrics-supported.md).
 
 ## Chart shows dashed line
 
-Azure metrics charts use dashed line style to indicate that there is a missing value (also known as “null value”) between two known time grain data points. For example, if in the time selector you picked “1 minute” time granularity but the metric was reported at 07:26, 07:27, 07:29, and 07:30 (note a minute gap between second and third data points), then a dashed line will connect 07:27 and 07:29 and a solid line will connect all other data points. The dashed line drops down to zero when the metric uses **count** and **sum** aggregation. For the **avg**, **min** or **max** aggregations, the dashed line connects two nearest known data points. Also, when the data is missing on the rightmost or leftmost side of the chart, the dashed line expands to the direction of the missing data point.
+Azure metrics charts use dashed line style to indicate that there's a missing value (also known as “null value”) between two known time grain data points. For example, if in the time selector you picked “1 minute” time granularity but the metric was reported at 07:26, 07:27, 07:29, and 07:30 (note a minute gap between second and third data points), then a dashed line will connect 07:27 and 07:29 and a solid line will connect all other data points. The dashed line drops down to zero when the metric uses **count** and **sum** aggregation. For the **avg**, **min** or **max** aggregations, the dashed line connects two nearest known data points. Also, when the data is missing on the rightmost or leftmost side of the chart, the dashed line expands to the direction of the missing data point.
   ![Screenshot that shows how when the data is missing on the rightmost or leftmost side of the chart, the dashed line expands to the direction of the missing data point.](./media/metrics-troubleshoot/dashed-line.png)
 
-**Solution:** This behavior is by design. It is useful for identifying missing data points. The line chart is a superior choice for visualizing trends of high-density metrics but may be difficult to interpret for the metrics with sparse values, especially when corelating values with time grain is important. The dashed line makes reading of these charts easier but if your chart is still unclear, consider viewing your metrics with a different chart type. For example, a scattered plot chart for the same metric clearly shows each time grain by only visualizing a dot when there is a value and skipping the data point altogether when the value is missing:
+**Solution:** This behavior is by design. It's useful for identifying missing data points. The line chart is a superior choice for visualizing trends of high-density metrics but may be difficult to interpret for the metrics with sparse values, especially when corelating values with time grain is important. The dashed line makes reading of these charts easier but if your chart is still unclear, consider viewing your metrics with a different chart type. For example, a scattered plot chart for the same metric clearly shows each time grain by only visualizing a dot when there's a value and skipping the data point altogether when the value is missing:
   ![Screenshot that highlights the Scatter chart menu option.](./media/metrics-troubleshoot/scatter-plot.png)
 
    > [!NOTE]
@@ -84,7 +84,7 @@ Azure metrics charts use dashed line style to indicate that there is a missing v
 ## Units of measure in metrics charts
 
 Azure monitor metrics uses SI based prefixes. Metrics will only be using IEC prefixes if the resource provider has chosen an appropriate unit for a metric.
-For ex: The resource provider Network interface (resource name: rarana-vm816) has no metric unit defined for "Packets Sent". The prefix used for the metric value here is k representing kilo (1000), a SI prefix. 
+For ex: The resource provider Network interface (resource name: rarana-vm816) has no metric unit defined for "Packets Sent". The prefix used for the metric value here's k representing kilo (1000), a SI prefix. 
 ![Screenshot that shows metric value with prefix kilo.](./media/metrics-troubleshoot/prefix-si.png)
 
 The resource provider Storage account (resource name: ibabichvm) has metric unit defined for "Blob Capacity" as bytes. Hence, the prefix used is mebi (1024^2), an IEC prefix.
@@ -122,13 +122,13 @@ IEC uses binary
 In many cases, the perceived drop in the metric values is a misunderstanding of the data shown on the chart. You can be misled by a drop in sums or counts when the chart shows the most-recent minutes because the last metric data points haven’t been received or processed by Azure yet. Depending on the service, the latency of processing metrics can be within a couple minutes range. For charts showing a recent time range with a 1- or 5- minute granularity, a drop of the value over the last few minutes becomes more noticeable:
     ![Screenshot that shows a drop of the value over the last few minutes.](./media/metrics-troubleshoot/unexpected-dip.png)
 
-**Solution:** This behavior is by design. We believe that showing data as soon as we receive it is beneficial even when the data is *partial* or *incomplete*. Doing so allows you to make important conclusion sooner and start investigation right away. For example, for a metric that shows the number of failures, seeing a partial value X tells you that there were at least X failures on a given minute. You can start investigating the problem right away, rather than wait to see the exact count of failures that happened on this minute, which might not be as important. The chart will update once we receive the entire set of data, but at that time it may also show new incomplete data points from more recent minutes.
+**Solution:** This behavior is by design. We believe that showing data as soon as we receive it's beneficial even when the data is *partial* or *incomplete*. Doing so allows you to make important conclusion sooner and start investigation right away. For example, for a metric that shows the number of failures, seeing a partial value X tells you that there were at least X failures on a given minute. You can start investigating the problem right away, rather than wait to see the exact count of failures that happened on this minute, which might not be as important. The chart will update once we receive the entire set of data, but at that time it may also show new incomplete data points from more recent minutes.
 
 ## Cannot pick Guest namespace and metrics
 
 Virtual machines and virtual machine scale sets have two categories of metrics: **Virtual Machine Host** metrics that are collected by the Azure hosting environment, and **Guest  (classic)** metrics that are collected by the [monitoring agent](../agents/agents-overview.md) running on your virtual machines. You install the monitoring agent by enabling [Azure Diagnostic Extension](../agents/diagnostics-extension-overview.md).
 
-By default, Guest (classic) metrics are stored in Azure Storage account, which you pick from the **Diagnostic settings** tab of your resource. If Guest metrics aren't collected or metrics explorer cannot access them, you will only see the **Virtual Machine Host** metric namespace:
+By default, Guest (classic) metrics are stored in Azure Storage account, which you pick from the **Diagnostic settings** tab of your resource. If Guest metrics aren't collected or metrics explorer cannot access them, you'll only see the **Virtual Machine Host** metric namespace:
 
 ![metric image](./media/metrics-troubleshoot/vm-metrics.png)