Merge pull request #101246 from bwren/am-manage-cost-storage

Azure Monitor cost storage update

Author: PRMerger6

articles/azure-monitor/platform/manage-cost-storage.md

@@ -39,6 +39,8 @@ The default pricing for Log Analytics is a **Pay-As-You-Go** model based on data
 In addition to the Pay-As-You-Go model, Log Analytics has **Capacity Reservation** tiers which enable you to save as much as 25% compared to the Pay-As-You-Go price. The capacity reservation pricing enables you to buy a reservation starting at 100 GB/day. Any usage above the reservation level will be billed at the Pay-As-You-Go rate. The Capacity Reservation tiers have a 31-day commitment period. During the commitment period, you can change to a higher level Capacity Reservation tier (which will restart the 31-day commitment period), but you cannot move back to Pay-As-You-Go or to a lower Capacity Reservation tier until after the commitment period is finished. 
 [Learn more](https://azure.microsoft.com/pricing/details/monitor/) about Log Analytics Pay-As-You-Go and Capacity Reservation pricing. 
 
+In all pricing tiers, the data volume is calculated from a string representation of the data as it is prepared to be stored. Several [properties common to all data types](https://docs.microsoft.com/azure/azure-monitor/platform/log-standard-properties) are not included in the calculation of the event size, including `_ResourceId`, `_ItemId`, `_IsBillable` and `_BilledSize`.
+
 Also, note that Some solutions, such as [Azure Security Center](https://azure.microsoft.com/pricing/details/security-center/) 
 and [Azure Sentinel](https://azure.microsoft.com/pricing/details/azure-sentinel/), have their own pricing model. 
 
@@ -162,6 +164,9 @@ When the daily limit is reached, the collection of billable data types stops for
 > [!NOTE]
 > The daily cap does not stop the collection of data from Azure Security Center, except for workspaces in which Azure Security Center was installed before June 19, 2017. 
 
+> [!NOTE]
+> Latency inherent in applying the daily cap can mean that the cap is not applied as precisely the specified daily cap level. 
+
 ### Identify what daily data limit to define
 
 Review [Log Analytics Usage and estimated costs](usage-estimated-costs.md) to understand the data ingestion trend and what is the daily volume cap to define. It should be considered with care, since you won’t be able to monitor your resources after the limit is reached.