docs: Document Linux-specific PAYG billing limitations for Arc SQL Server

MikeRayMSFT · MikeRayMSFT · commit 9a9a51b8794b · 2026-04-01T14:30:29.000-07:00
diff --git a/docs/sql-server/azure-arc/faq.yml b/docs/sql-server/azure-arc/faq.yml
@@ -3,7 +3,8 @@ metadata:
   title: Frequently asked questions
   description: Provides questions and answers frequently asked about SQL Server enabled by Azure Arc.
   ms.topic: faq
-  ms.date: 02/25/2025
+  ms.date: 04/01/2026
+  ai-usage: ai-assisted
   ms.author: mikeray
   author: MikeRayMSFT
 title: Frequently asked questions - SQL Server enabled by Azure Arc
@@ -70,6 +71,18 @@ sections:
           - Write your own ARG query to get the billing mode and last billed data points.
           - Subscribe to Activity Log events for when usage records are not received when expected or when recurring billing starts or is happening. Review [Use activity logs with SQL Server enabled by Azure Arc](activity-logs.md).
 
+      - question: Does pay-as-you-go billing work on Linux?
+        answer: |
+          Yes. PAYG billing is supported for SQL Server on Linux with limitations. Passive instance detection, connected user verification, and Database Engine-level core visibility aren't available on Linux. All SQL Server instances on Linux are billed as active. For details, see [Manage licensing and billing](manage-license-billing.md).
+
+      - question: Why are my passive SQL Server instances on Linux billed as active with pay-as-you-go?
+        answer: |
+          Passive instance detection isn't available on Linux. Without this capability, the free passive billing benefit can't be applied. All instances are billed based on the OS-reported core count. If you need free passive instance billing, consider using volume licensing instead of PAYG.
+
+      - question: How does core detection work for PAYG on Linux?
+        answer: |
+          On Linux, core count is reported based on the operating system environment (virtual or physical cores visible to the OS). Database Engine-level core verification isn't available. Billing is based on the OS-reported core count, subject to the four-core minimum per OSE.
+
   - name: Security
     questions:
       - question: What are the best practices for security?
diff --git a/docs/sql-server/azure-arc/includes/features-operating-system.md b/docs/sql-server/azure-arc/includes/features-operating-system.md
@@ -2,7 +2,7 @@
 author: MikeRayMSFT
 ms.author: mikeray
 ms.reviewer: randolphwest
-ms.date: 05/10/2023
+ms.date: 04/01/2026
 ms.topic: include
 ms.custom: ignite-2023
 ---
@@ -11,7 +11,7 @@ The following table identifies features available by operating system:
 | Feature | Windows | Linux |
 | --- | --- | --- |
 | [Discover and register SQL Server instances in Azure](../prerequisites.md) | Yes | Yes |
-| [Azure pay-as-you-go billing](../manage-configuration.md) | Yes | Yes |
+| [Azure pay-as-you-go billing](../manage-configuration.md) | Yes | Yes <sup>2</sup> |
 | [Install Azure extension for SQL Server during setup](../../../database-engine/install-windows/install-sql-server-from-the-installation-wizard-setup.md#install-sql-server-2022) <sup>1</sup> | Yes | No |
 | [Best practices assessment](../assess.md) | Yes | No |
 | [Migration assessment](../migration-assessment.md) | Yes | No |
@@ -31,3 +31,5 @@ The following table identifies features available by operating system:
 | [Operate with least privilege](../configure-least-privilege.md)| Yes | No |
 
 <sup>1</sup> [!INCLUDE [sssql22-md](../../../includes/sssql22-md.md)] only.
+
+<sup>2</sup> PAYG billing is supported on Linux with limitations. Passive instance detection, connected user verification, and Database Engine-level core visibility aren't available. All instances are billed as active. For details, see [Manage licensing and billing](../manage-license-billing.md).
diff --git a/docs/sql-server/azure-arc/manage-configuration.md b/docs/sql-server/azure-arc/manage-configuration.md
@@ -4,7 +4,8 @@ description: Learn how to manage configuration options for SQL Server enabled by
 author: anosov1960
 ms.author: sashan
 ms.reviewer: mikeray, randolphwest
-ms.date: 07/03/2025
+ms.date: 04/01/2026
+ai-usage: ai-assisted
 ms.topic: how-to
 ms.custom: sfi-image-nochange
 ---
@@ -87,6 +88,9 @@ There are two ways to configure the SQL Server host in the Azure portal:
 
 Choose one of the license types. For descriptions, see [License types](manage-license-billing.md#license-types).
 
+> [!NOTE]
+> On Linux, certain configuration features aren't available, including passive instance detection and connected user verification. When you configure PAYG billing on Linux, all instances are billed as active regardless of their HA/DR role. For details, see [Manage licensing and billing](manage-license-billing.md).
+
 <a id="use-physical-core-license"></a>
 
 #### Use a physical core license
diff --git a/docs/sql-server/azure-arc/manage-license-billing.md b/docs/sql-server/azure-arc/manage-license-billing.md
@@ -4,7 +4,7 @@ description: This article explains how to manage SQL Server licensing options. I
 author: anosov1960
 ms.author: sashan
 ms.reviewer: mikeray, randolphwest, maghan, mathoma
-ms.date: 03/04/2026
+ms.date: 04/01/2026
 ai-usage: ai-assisted
 ms.topic: how-to
 ms.custom:
@@ -98,6 +98,15 @@ The following license types are supported when you're licensing v-cores:
 
 - If you're using an Azure subscription managed by a Cloud Service Provider (CSP), enabling pay-as-you-go requires that you or the CSP consents to recurrent billing. For details, review [Manage recurrent billing for SQL Server enabled by Azure Arc with pay-as-you-go license](manage-pay-as-you-go-transition.md).
 
+> [!IMPORTANT]
+> **Pay-as-you-go on Linux**: The following PAYG limitations apply to SQL Server on Linux:
+>
+> - **Passive instance detection**: Automatic detection of passive replicas in availability groups or failover cluster instances isn't available. All instances are billed as active.
+> - **Core visibility**: Core count is based on the operating system environment. Database Engine-level core verification isn't available.
+> - **Connected user detection**: Verification of active user connections on readable secondary replicas isn't available.
+>
+> These limitations don't affect license compliance or the ability to use PAYG billing on Linux. However, you should account for the billing differences when planning PAYG deployments on Linux. For more information about feature availability by operating system, see [Feature availability by operating system](overview.md#feature-availability-by-operating-system).
+
 - By selecting a license with Software Assurance, you attest that you have Enterprise or Standard licenses with active Software Assurance or an active SQL Server subscription license, and that the device is in compliance with the [Product Terms outsourcing restrictions](https://www.microsoft.com/licensing/terms/productoffering/MicrosoftAzure/allprograms#:~:text=When%20using%20SQL%20Server%20enabled%20by%20Azure%20Arc%20with%20a,%2C%20regardless%20of%20whether%20those%20Servers%20are%20dedicated%20to%20Customer).
 
 - For SQL Server Enterprise, Standard, or Web edition instances of SQL Server licensed from cloud service providers or hosting service providers using the Service Provider Licensing Agreement (SPLA), use `license only` for the license type. Web edition isn't available in [!INCLUDE [sssql25-md](../../includes/sssql25-md.md)] and later versions.
@@ -292,6 +301,7 @@ The current passive instance detection logic has the following limitations:
 - Passive instances for other disaster recovery technologies like log shipping or mirroring aren't automatically detected at this time.
 - The detection logic doesn't support free disaster recovery testing.
 - The detection logic doesn't support monitoring connections like database consistency checks, backups, or monitoring resource usage data.
+- On Linux, passive instance detection isn't available. All SQL Server instances on Linux are billed as active, regardless of their HA/DR role.
 
 If you're unable to work within these limitations, you can use volume licensing instead of `PAYG`. For details, review [Configure SQL Server enabled by Azure Arc](manage-configuration.md).
 
diff --git a/docs/sql-server/azure-arc/manage-pay-as-you-go-transition.md b/docs/sql-server/azure-arc/manage-pay-as-you-go-transition.md
@@ -4,7 +4,8 @@ description: How to transition SQL Server from the legacy licensing model to Azu
 author: anosov1960
 ms.author: sashan
 ms.reviewer: mikeray, randolphwest, maghan
-ms.date: 07/08/2025
+ms.date: 04/01/2026
+ai-usage: ai-assisted
 ms.topic: how-to
 ---
 
@@ -71,6 +72,17 @@ Azure Arc-connected servers must check in with Azure at least once every 30 days
 
 You or your cloud solutions provider must explicitly provide consent before you enabled pay-as-you-go billing. For details, review [Recurring billing consent](#recurring-billing-consent).
 
+## Linux-specific considerations
+
+When transitioning SQL Server on Linux to pay-as-you-go, be aware of the following limitations compared to Windows:
+
+- **Passive instance detection**: Automatic detection of passive replicas in availability groups or failover cluster instances isn't available on Linux. All instances are billed as active.
+- **Core detection**: Core count is reported based on the operating system environment. Database Engine-level core verification isn't available.
+- **Connected user detection**: Verification of active user connections on readable secondary replicas isn't available.
+- **Agent health monitoring**: Ensure the Azure Connected Machine agent stays healthy and connected. The 30-day reconnection window and recurring billing behavior work the same as on Windows.
+
+These limitations don't block the transition to PAYG on Linux. However, plan for the billing differences described in [Manage licensing and billing](manage-license-billing.md).
+
 ### Reconnection within 30 days
 
 If the machine reconnects within 30 days of being disconnected, pay-as-you-go billing is based on the actual usage logs maintained locally by the extension.
diff --git a/docs/sql-server/azure-arc/overview.md b/docs/sql-server/azure-arc/overview.md
@@ -4,7 +4,8 @@ description: Feature overview. Explains how you can manage instances of SQL Serv
 author: anosov1960
 ms.author: sashan
 ms.reviewer: mikeray, randolphwest
-ms.date: 06/09/2025
+ms.date: 04/01/2026
+ai-usage: ai-assisted
 ms.topic: concept-article
 ms.custom: references_regions
 ---
@@ -73,6 +74,9 @@ Microsoft Purview provides a unified data governance solution to help manage and
 
 Now, with [!INCLUDE [ssazurearc](../../includes/ssazurearc.md)], you have the option of purchasing SQL Server using a 'pay-as-you-go' model instead of purchasing licenses. This model is a great alternative if you're looking to save costs on SQL Server instances that have variable demand for compute capacity over time. For example, when you can turn off a SQL Server at night or on weekends, or even just scale down the number of cores used during less busy times. It's also a great option if you only plan to use a SQL Server for a short period of time and then won't need it anymore. Pay-as-you-go, billed through Azure, is now available for all versions of SQL Server from 2012 to 2022.
 
+> [!NOTE]
+> On Linux, certain PAYG features aren't available, including automatic passive instance detection and connected user verification. All SQL Server instances on Linux are billed as active. For details, see [Manage licensing and billing](azure-arc/manage-license-billing.md).
+
 ## Extended Security Updates (ESU)
 
 Once [!INCLUDE [ssNoVersion](../../includes/ssnoversion-md.md)] has reached the end of its support lifecycle, you can sign up for an Extended Security Update (ESU) subscription for your servers and remain protected for up to three years. When you upgrade to a newer version of [!INCLUDE [ssNoVersion](../../includes/ssnoversion-md.md)], your ESU subscription is automatically canceled. When you [migrate to Azure SQL](/azure/azure-sql/migration-guides/), the ESU charges automatically stop but you continue to have access to the ESUs.
