KQL Get Used Capacity on Storage Account

Question

is there a way to query all storage accounts in subscriptions called "storage" and get the used capacity for each one. I'm trying to create an alert rule if they exceed 1024 gb capacity, but I'm not seeing used capacity anywhere. You can go into each storage account and configure the alert within the storage account, but that's not practical.

I can get some information from storage account using, this for availability:

AzureMetrics 
| where TimeGenerated > ago(1d)
| where ResourceProvider == "MICROSOFT.STORAGE"
| where _ResourceId contains "storage"
| where MetricName =~ "availability"
| project TimeGenerated, ResourceGroup, _SubscriptionId, Resource, MetricName, Average, UnitName

Thanks in advance :)

Answer 1

UsedCapacity

Exporting platform metrics to other locations

Using diagnostic settings is the easiest way to route the metrics, but there are some limitations:
Exportability. All metrics are exportable through the REST API, but some can't be exported through diagnostic

Microsoft.Storage/storageAccounts

Metric	Exportable via Diagnostic Settings?	Metric Display Name	Unit	Aggregation Type	Description	Dimensions
UsedCapacity	Yes	Used capacity	Bytes	Average	The amount of storage used by the storage account. For standard storage accounts, it's the sum of capacity used by blob, table, file, and queue. For premium storage accounts and Blob storage accounts, it is the same as BlobCapacity or FileCapacity.	No Dimensions

AzureMetrics
|   where ResourceProvider  == "MICROSOFT.STORAGE"
|   where MetricName        == "UsedCapacity"
|   where SubscriptionId    == "ebb79bc0-aa86-44a7-8111-cabbe0c43993"
|   summarize arg_max(TimeGenerated, ResourceGroup, Resource, Average) by _ResourceId

Fiddle