A. Server 2008 R2 is the minor update to Server 2008 and builds on the Server 2008 code base and adds a number of core improvements and new features, including the following:
• Support for 256 processors
• Dispatcher Lock enhancement, which removes a problem for large multi-core systems where locks would cause significant processor waste. In addition, changes were made to the Page Frame Number (PFN) lock to remove a lock of the entire PFN table, which again improves scalability. Desktop systems with a few cores will not see any real performance improvement.
• Power Management improvements that allow cores to be "parked" if not needed to save power consumption. Essentially the OS will try and run all the work on the fewest number of cores. It also has centralized power policy control enabling different policies to be applied during non-peak hours. Each core can also be configured to run at different frequencies, which again helps reduce power consumption
• Server Core has PowerShell support
• Server Manager can remotely manage other Server 2008 R2 server installations
• Migration tools and wizards to migrate services from Windows 2003/2008 to 2008 R2. This includes solutions around Active Directory (AD), DHCP, DNS, file, and print
• Best practices analyzer built into Server Manager
• PowerShell 2.0 which has a new graphical interface and new cmdlets with improved integration with AD, IIS and Power Management including one-to-many remote management using WS-MGMT
• Hyper-V version 2 with Live Migration support which does not require any changes to the virtual machines (VMs), the storage infrastructure, or the network infrastructure. The only requirement is the VHD file for the VM must be stored within the ClusterStorage area of the 2008 R2 cluster. In addition:
- Support for 32 logical processors on host computer
- Second Level Translation (SLAT) which is a processor enhancement for virtualization which reduces overhead of hypervisors
- Hot Add/Remove of VHD disks to a VM while running
- General improvements helping VDI, dynamic data center and server consolidation scenarios
• Microsoft Failover Clustering changes, including the Cluster Shared Volumes (CSV), which allows multiple nodes in failover cluster to concurrently access the same LUN via a special folder, ClusterStorage, which allows each VM to believe it has its own LUN. Each VHD is placed in a subdirectory of the ClusterStorage folder. This feature is only for LiveMigration. Dynamic I/O redirection allows the I/O from one node to be actioned by another node should a node lose connectivity to the storage target. A Best Practice Analyzer is also provided to ensure optimum cluster configuration. A rolling upgrade from a Windows 2003/2008 to a 2008 R2 cluster is not possible. You will need to create a new 2008 R2 cluster and migrate the services.
• DirectAccess, which allows Windows 7 clients to access corporate resources without establishing a VPN so the user has a seamless experience
• BranchCache, which enables a server in a branch location to cache HTTP and SMB acquired information that has been requested by a client. When a client wants a file, the server sends the client back a hash that represents the file and the client asks the server if the file is available and if not the server gets the file from the client to enable it to serve subsequent requests from other clients. This can also be used in a peer-to-peer mode where the client sends a broadcast on its subnet with the hash and peers respond if they have the file
• Enhanced IIS 7 platform, which includes ASP.NET on server core, integrated FTP and WebDav, new IIS manager modules, and enhanced logging and tracing
• DHCP failover capabilities so a primary and secondary DHCP server sync information and the secondary provides addresses if the primary becomes unavailable
• DNS Security improvements, which can include using PKI to secure DNS resource records
• Improved AD identity management solution. In addition:
- Recycle bin feature for deleted AD objects. Needs the new 2008 R2 forest functional level
- Offline domain-joining capability
- Active Directory Administrative Center management console
- Managed service accounts, which are accounts used by services and when the password is changed the services using the account has the password updated automatically
• New read-only capabilities for Distributed File System (DFS) replicas, which are very useful for branch locations
• BitLocker improvements including support for eSATA hard disks, USB hard and flash drive, and CompactFlash devices with BitLocker encryption