|Version of the Windows NT operating system|
|OS family||Microsoft Windows|
|Released to |
|July 22, 2009|
|October 22, 2009|
|Latest release||Service Pack 1 with security update rollup (6.1.7601.24499) / March 19, 2019|
|Update method||Windows Update, Windows Server Update Services, SCCM|
|Kernel type||Hybrid (Windows NT kernel)|
|Windows shell (Graphical)|
|License||Commercial software (Retail, volume licensing, Microsoft Software Assurance)|
|Preceded by||Windows Server 2008 (2008)|
|Succeeded by||Windows Server 2012 (2012)|
|Mainstream support ended on January 13, 2015.|
Extended support ended January 14, 2020.
Windows Server 2008 R2 is eligible for the paid ESU (Extended Security Updates) program. This program allowed volume license customers to purchase, in yearly installments, security updates for the operating system until January 10, 2023, only for Standard, Enterprise and Datacenter volume licensed editions. The program is included with Microsoft Azure purchases, and offers Azure customers an additional year of support, until January 9, 2024. 
Installing Service Pack 1 is required for users to receive updates and support after April 9, 2013.
|Part of a series of articles on|
Windows Server 2008 R2, codenamed "Windows Server 7", is the fifth version of the Windows Server operating system produced by Microsoft and released as part of the Windows NT family of operating systems. It was released to manufacturing on July 22, 2009, and became generally available on October 22, 2009, shortly after the completion of Windows 7. It is the successor to Windows Server 2008, which is derived from the Windows Vista codebase, released the previous year, and was succeeded by the Windows 8-based Windows Server 2012.
Enhancements in Windows Server 2008 R2 include new functionality for Active Directory, new virtualization and management features, version 7.5 of the Internet Information Services web server and support for up to 256 logical processors. It is built on the same kernel used with the client-oriented Windows 7, and is the first server operating system released by Microsoft to exclusively support 64-bit processors, a move which was followed by the consumer-oriented Windows 11 in 2021. Windows Server 2008 R2 is also the last version of Windows to support Itanium processors; its successor, Windows Server 2012, supports x64 processors only.
Seven editions of Windows Server 2008 R2 were released: Foundation, Standard, Enterprise, Datacenter, Web, HPC Server and Itanium, as well as Windows Storage Server 2008 R2. A home server variant called Windows Home Server 2011 was also released.
Microsoft introduced Windows Server 2008 R2 at the 2008 Professional Developers Conference as the server variant of Windows 7, based on the Windows NT kernel.
On January 7, 2009, a beta release of Windows Server 2008 R2 was made available to subscribers of Microsoft's TechNet and MSDN programs, as well as those participating in the Microsoft Connect program for Windows 7. Two days later, the beta was released to the public via the Microsoft Download Center.
On April 30, 2009, the release candidate was made available to subscribers of TechNet and MSDN. On May 5, 2009, the release candidate was made available to the general public via the Microsoft download center.
According to Windows Server Blog, the following are the dates of the year 2009 when Microsoft Windows Server 2008 R2 has been made available to various distribution channels:
Additionally, qualifying students have been able to download Windows Server 2008 R2 Standard edition in 15 languages from the Microsoft Imagine program (known as DreamSpark at the time).
Microsoft has announced that Server 2008 R2 will be the last version of Windows supporting the Itanium architecture, with its extended support ending earlier than for x86-64 editions or "until July 10, 2018."
See also: Features new to Windows 7
A reviewer guide published by the company describes several areas of improvement in R2. These include new virtualization capabilities (Live Migration, Cluster Shared Volumes using Failover Clustering and Hyper-V), reduced power consumption, a new set of management tools and new Active Directory capabilities such as a "recycle bin" for deleted objects. IIS 7.5 has been added to this release which also includes updated FTP server services. Security enhancements include encrypted clientless authenticated VPN services through DirectAccess for clients using Windows 7, and the addition of DNSSEC support for DNS Server Service. Even though DNSSEC as such is supported, only one signature algorithm is available: #5/RSA/SHA-1. Since many zones use a different algorithm – including the root zone – this means that in reality Windows still can't serve as a recursive resolver.
The DHCP server supports a large number of enhancements such as MAC address-based control filtering, converting active leases into reservations or link layer based filters, DHCppP Name protection for non-Windows machines to prevent name squatting, better performance through aggressive lease database caching, DHCP activity logging, auto-population of certain network interface fields, a wizard for split-scope configuration, DHCP Server role migration using WSMT, support for DHCPv6 Option 15 (User Class) and Option 32 (Information Refresh Time). The DHCP server runs in the context of the Network Service account which has fewer privileges to reduce potential damage if compromised.
Windows Server 2008 R2 supports up to 64 physical processors or up to 256 logical processors per system. (Only the Datacenter and Itanium editions can take advantage of the capability of 64 physical processors. Enterprise, the next-highest edition after those two, can only use 8.) When deployed in a file server role, new File Classification Infrastructure services allow files to be stored on designated servers in the enterprise based on business naming conventions, relevance to business processes and overall corporate policies.
Server Core includes a subset of the .NET Framework, so that some applications (including ASP.NET web sites and Windows PowerShell 2.0) can be used.
Performance improvement was a major area of focus for this release; Microsoft has stated that work was done to decrease boot time, improve the efficiency of I/O operations while using less processing power, and generally improve the speed of storage devices, especially iSCSI.
Active Directory has several new features when raising the forest and domain functional levels to Windows Server 2008 R2: Two added features are Authentication Mechanism Assurance and Automatic SPN Management. When raising the forest functional level, the Active Directory recycle bin feature is available and can be enabled using the Active Directory Module for PowerShell.
Support for the RTM version of Windows Server 2008 R2 ended on April 9, 2013. Users had to install Service Pack 1 to continue receiving updates.
On January 13, 2015, Windows Server 2008 R2 exited mainstream support and entered the extended support phase; Microsoft continued to provide security updates every month for Windows Server 2008 R2, however, free technical support, warranty claims, and design changes were no longer offered. Extended support ended on January 14, 2020, about ten years after the release of Windows Server 2008 R2. On July 12, 2018, Microsoft announced a paid "Extended Security Updates" service that will offer additional updates for Windows Server 2008 R2 Standard, Enterprise and Datacenter for up to 3 years after the end of extended support, lasting until January 10, 2023. In November 2021, Microsoft extended ESU support for Windows Server 2008 R2 until January 9, 2024, only for Microsoft Azure customers.
In August 2019, researchers reported that "all modern versions of Microsoft Windows" may be at risk for "critical" system compromise due to design flaws of hardware device drivers from multiple providers. In the same month, computer experts reported that the BlueKeep security vulnerability, CVE-2019-0708, that potentially affects older unpatched Microsoft Windows versions via the program's Remote Desktop Protocol, allowing for the possibility of remote code execution, may now include related flaws, collectively named DejaBlue, affecting newer Windows versions (i.e., Windows 7 and all recent versions) as well. In addition, experts reported a Microsoft security vulnerability, CVE-2019-1162, based on legacy code involving Microsoft CTF and ctfmon (ctfmon.exe), that affects all Windows versions from the older Windows XP version to the most recent Windows 10 versions; a patch to correct the flaw is currently available.
On February 9, 2011, Microsoft officially released Service Pack 1 (SP1) for Windows 7 and Windows Server 2008 R2 to OEM partners. Apart from bug fixes, it introduces two new major functions, RemoteFX and Dynamic Memory. RemoteFX enables the use of graphics hardware support for 3D graphics in a Hyper-V based VM. Dynamic Memory makes it possible for a VM to only allocate as much physical RAM as is needed temporarily for its execution. On February 16, SP1 became available for MSDN and TechNet subscribers as well as volume licensing customers. As of February 22, SP1 is generally available for download via the Microsoft Download Center and available on Windows Update.
System requirements for Windows Server 2008 R2 are as follows:
|Maximum RAM on x86-64||8 GB||32 GB||256 GB||2 TB|
|Maximum physical CPUs||1||4||8||64|
|Failover cluster nodes (Nodes)||—||—||—||—||16||8|
|Cross-file replication (DFS-R)||No||Yes||Yes||Yes||Yes||Yes||Yes|
|Fault tolerant memory sync||No||No||No||No||Yes||Yes||Yes|
|Memory modules: Hot addition||No||No||No||No||Yes||Yes||Yes|
|Memory modules: Hot replacement||No||No||No||No||No||Yes||Yes|
|CPUs: Hot addition||No||No||No||No||No||Yes||Yes|
|CPUs: Hot replacement||No||No||No||No||No||Yes||Yes|
|Remote Desktop Services connections||50||250||No||No||Unlimited||Unlimited||No|
|Virtual image use rights||Forbidden||Host + 1 VM||1 VM||Host + 1 VM||Host + 4 VMs||Unlimited||Unlimited|
Why the change? The natural evolution of the x86 64-bit ("x64") architecture has led to the creation of processors and servers which deliver the scalability and reliability needed for today's "mission-critical" workloads.
SQL Server 2008 R2 and Visual Studio 2010 are also the last versions to support Itanium.