Learn Editor: Update resource-manager-alerts-log.md

Author: quillanogle

articles/azure-monitor/alerts/resource-manager-alerts-log.md

@@ -14,6 +14,9 @@ This article includes samples of [Azure Resource Manager templates](../../azure-
 
 [!INCLUDE [azure-monitor-samples](../../../includes/azure-monitor-resource-manager-samples.md)]
 
+> [!NOTE]
+> The combined size of all data in the log alert rule properties cannot exceed 64KB. This can be caused by too many dimensions, the query being too large, too many action groups, or a long description. When creating a large alert rule, remember to optimize these areas.
+
 ## Template for all resource types (from version 2021-08-01)
 
 The following sample creates a rule that can target any resource.