Create memory management article and update Kestrel overview

Co-authored-by: tdykstra <[email protected]>

Author: Copilot

aspnetcore/fundamentals/servers/kestrel.md

@@ -5,7 +5,7 @@ description: Learn about Kestrel, the cross-platform web server for ASP.NET Core
 monikerRange: '>= aspnetcore-3.1'
 ms.author: tdykstra
 ms.custom: mvc
-ms.date: 08/25/2025
+ms.date: 12/04/2025
 uid: fundamentals/servers/kestrel
 ---
 # Kestrel web server in ASP.NET Core
@@ -14,7 +14,7 @@ uid: fundamentals/servers/kestrel
 
 By [Tom Dykstra](https://github.com/tdykstra), [Chris Ross](https://github.com/Tratcher), and [Stephen Halter](https://twitter.com/halter73)
 
-:::moniker range=">= aspnetcore-10.0"
+:::moniker range=">= aspnetcore-8.0"
 
 Kestrel is a cross-platform [web server for ASP.NET Core](xref:fundamentals/servers/index). Kestrel is the recommended server for ASP.NET Core, and it's configured by default in ASP.NET Core project templates.
 
@@ -33,7 +33,7 @@ Kestrel's features include:
   * Building a reverse proxy with [YARP](https://github.com/microsoft/reverse-proxy).
 * **Extensibility:** Customize Kestrel through configuration, middleware, and custom transports.
 * **Performance diagnostics:** Kestrel provides built-in performance diagnostics features, such as logging and metrics.
-* **Memory management:** Kestrel includes features for efficient memory management, such as automatic eviction from memory pool.
+* **Memory management:** Kestrel includes features for efficient memory management. For more information, see <xref:fundamentals/servers/kestrel/memory-management>.
 
 ## Get started
 
@@ -43,13 +43,6 @@ ASP.NET Core project templates use Kestrel by default when not hosted with IIS.
 
 For more information on configuring `WebApplication` and `WebApplicationBuilder`, see <xref:fundamentals/minimal-apis>.
 
-## Optional client certificates
-
-For information on apps that must protect a subset of the app with a certificate, see [Optional client certificates](xref:security/authentication/certauth#optional-client-certificates).
-
-
-[!INCLUDE[](includes/memory-eviction2.md)]
-
 ## Additional resources
 
 <a name="endpoint-configuration"></a>

aspnetcore/fundamentals/servers/kestrel/includes/kestrel6.md

@@ -21,10 +21,6 @@ ASP.NET Core project templates use Kestrel by default when not hosted with IIS.
 
 For more information on configuring `WebApplication` and `WebApplicationBuilder`, see <xref:fundamentals/minimal-apis>.
 
-## Optional client certificates
-
-For information on apps that must protect a subset of the app with a certificate, see [Optional client certificates](xref:security/authentication/certauth#optional-client-certificates).
-
 ## Behavior with debugger attached
 
 The following timeouts and rate limits aren't enforced when a debugger is attached to a Kestrel process:
@@ -82,10 +78,6 @@ ASP.NET Core project templates use Kestrel by default when not hosted with IIS.
 
 For more information on building the host, see the *Set up a host* and *Default builder settings* sections of <xref:fundamentals/host/generic-host#set-up-a-host>.
 
-## Optional client certificates
-
-For information on apps that must protect a subset of the app with a certificate, see [Optional client certificates](xref:security/authentication/certauth#optional-client-certificates).
-
 ## Additional resources
 
 <a name="endpoint-configuration"></a>

aspnetcore/fundamentals/servers/kestrel/memory-management.md

@@ -0,0 +1,43 @@
+---
+title: Memory management in Kestrel
+author: tdykstra
+description: Learn about memory management in Kestrel, including automatic eviction from memory pools and using memory pool metrics.
+monikerRange: '>= aspnetcore-8.0'
+ms.author: tdykstra
+ms.date: 12/04/2024
+uid: fundamentals/servers/kestrel/memory-management
+---
+
+# Memory management in Kestrel
+
+[!INCLUDE[](~/includes/not-latest-version.md)]
+
+By [Tom Dykstra](https://github.com/tdykstra)
+
+This article provides guidance for managing memory in Kestrel, including automatic eviction from memory pools and using memory pool metrics.
+
+## Automatic eviction from memory pool
+
+The memory pools used by Kestrel, IIS, and HTTP.sys automatically evict memory blocks when the application is idle or under low load. The feature runs automatically and doesn't need to be enabled or configured manually.
+
+In versions of .NET earlier than 10, memory allocated by the pool remains reserved, even when not in use. This automatic eviction feature reduces overall memory usage and helps applications stay responsive under varying workloads.
+
+### Use memory pool metrics
+
+The default memory pool used by the ASP.NET Core server implementations includes metrics, which can be used to monitor and analyze memory usage patterns. The metrics are under the name `"Microsoft.AspNetCore.MemoryPool"`.
+
+For information about metrics and how to use them, see <xref:log-mon/metrics/metrics>.
+
+## Manage memory pools
+
+Besides using memory pools efficiently by evicting unneeded memory blocks, ASP.NET Core provides a built-in [IMemoryPoolFactory](https://source.dot.net/#Microsoft.AspNetCore.Connections.Abstractions/IMemoryPoolFactory.cs) and an implementation. It makes the implementation available to your application through dependency injection.
+
+The following code example shows a simple background service that uses the built-in memory pool factory implementation to create memory pools. These pools benefit from the automatic eviction feature:
+
+:::code language="csharp" source="~/fundamentals/servers/snippets/10.x/my-background-service.cs":::
+
+To use a custom memory pool factory, make a class that implements `IMemoryPoolFactory` and register it with dependency injection, as the following example does. Memory pools created this way also benefit from the automatic eviction feature:
+
+:::code language="csharp" source="~/fundamentals/servers/snippets/10.x/memory-pool-factory.cs":::
+
+When you're using a memory pool, be aware of the pool's <xref:System.Buffers.MemoryPool`1.MaxBufferSize>.

aspnetcore/toc.yml

@@ -1190,6 +1190,9 @@ items:
           - name: Diagnostics
             displayName: diagnostics
             uid: fundamentals/servers/kestrel/diagnostics
+          - name: Memory management
+            displayName: memory, pool, kestrel
+            uid: fundamentals/servers/kestrel/memory-management
           - name: HTTP/2
             displayName: deploy, publish, server, Kestrel
             uid: fundamentals/servers/kestrel/http2