Add public metrics documentation about IEC vs SI

Add public metrics documentation about IEC vs SI

Author: rakeshrana44

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

@@ -70,6 +70,40 @@ Azure metrics charts use dashed line style to indicate that there is a missing v
    > [!NOTE]
    > If you still prefer a line chart for your metric, moving mouse over the chart may help to assess the time granularity by highlighting the data point at the location of the mouse pointer.
 
+## Prefixes of metrics
+
+By default 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. 
+![Screenshot that shows metric value with prefix kilo.](./media/metrics-troubleshoot/prefixSI.png)
+
+And 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.
+![Screenshot that shows metric value with prefix mebi.](./media/metrics-troubleshoot/prefixIEC.png)
+
+SI uses decimal
+|   Value   | abbreviation |          SI         |
+|-----------|--------------|---------------------|
+|   1000	  |  k	 | kilo  |
+|   1000^2  |  M   | mega  |
+|   1000^3  |  G	 | giga  |
+|   1000^4  |  T	 | tera  |
+|   1000^5  |  P	 | peta  |
+|   1000^6  |  E	 | exa   |
+|   1000^7  |  Z   | zetta |
+|   1000^8  |  Y	 | yotta |
+
+IEC uses binary
+|Value| abbreviation|	IEC | Legacy ||
+|-----|-------------|-----|----|----|
+|1024	| Ki|	kibi|	K	| kilo|
+|1024^2|	Mi|	mebi|	M	| mega|
+|1024^3|	Gi|	gibi|	G	| giga|
+|1024^4|	Ti|	tebi|	T	| tera|
+|1024^5|	Pi|	pebi|	-	||
+|1024^6|	Ei|	exbi|	-	||
+|1024^7|	Zi|	zebi|	-	||
+|1024^8|	Yi|	yobi| - ||
+
+
 ## Chart shows unexpected drop in values
 
 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: