Windows Server 2008 R2 brings a lot of improvements in the virtualization area. Some of the top improvements include:
1. Hot-Add VM Storage
Windows Server 2008 R2 Hyper-V supports hot plug-in and hot removal of disk storage in the format of Virtual Hard Drive (VHD) files and/or pass-through disks. This can be done while a VM is running, and allows administrators to meet changing workload requirements.
2. Enhanced Processor Support
64 Logical Processors per host – Windows Server 2008 R2 Hyper-V supports up to 64 logical processor cores, making it possible to run even more demanding workloads on a single physical computer, or consolidate more workloads on a single physical computer.
Second-Level Address Translation (SLAT) – Windows Server 2008 R2 Hyper-V also supports Second-Level Address Translation (SLAT) that uses special CPU functions available in Intel processors that support Extended Page tables and AMD processors that support Rapid Virtualization Indexing to perform more VM memory management functions and reduce the overhead of translating guest physical addresses to real physical addresses. By doing this, Hypervisor CPU time is significantly reduced, and more memory is saved for each VM.
CPU Core Parking – CPU Core Parking enables power savings by scheduling VM execution on only some of a server’s CPU cores and placing the rest in a sleep state.
Processor Compatibility Mode – Processor Compatibility Mode works by hiding a fixed set of processor features that differ among members of the same processor architecture. It brings the benefits of live migration, Quick Migration, and Failover Clustering to scenarios where cluster hardware cannot be completely standardized by using identical processor types on all cluster members.
3. Enhanced Networking Support
Jumbo Frames – Support for Jumbo frames enables VMs to use bigger (Jumbo) Frames up to 9014 bytes if the underlying physical network supports it. This reduces the network stack overhead incurred per byte and increases throughput. In addition, there is a significant reduction of CPU utilization due to the fewer number of calls from the network stack to the network driver.
Extended TCP Chimney support for VMs – TCP Chimney allows the offloading of TCP/IP processing to the network hardware has been extended to the virtual environment. TCP Chimney improves VM performance by allowing the VM to offload network processing to hardware, especially on networks with bandwidth over 1 Gigabit. This feature is especially beneficial for roles involving large amounts of data transfer, such as the file server role.
Virtual Machine Queue (VMQ) – Virtual Machine Queue (VMQ) allows physical computer Network Interface Cards to use direct memory access (DMA) to place the contents of packets directly into VM memory, increasing I/O performance.
4. Cluster Shared Volumes (CSV)
Windows Server 2008 R2 enables a new storage type called Cluster Shared Volumes (or CSV). CSV enables multiple Windows Servers to access SAN storage using a single consistent namespace for all volumes on all hosts. Multiple hosts can access the same Logical Unit Number (LUN) on SAN storage. Available only for the Hyper-V role, Hyper-V uses CSV storage to simplify and enhance shared storage usage. CSV enables faster live migration and easier storage management for Hyper-V when used in a cluster configuration. Cluster Shared Volumes is available as part of the Windows Failover Clustering feature of Windows Server 2008 R2.
5. Live Migration
Windows Server 2008 R2 Hyper-V provides greater flexibility with live migration. Live migration is integrated with Windows Server 2008 R2 Hyper-V and Microsoft Hyper-V Server 2008 R2. With Hyper-V live migration, you can move running VMs from one Hyper-V physical host to another, without any disruption or perceived loss of service. Live Migration provides the following benefits:
Better agility – Data centers with multiple Hyper-V physical hosts can move running VMs to the best physical computer for performance, scaling, or optimal consolidation without affecting users.
Reduces costs and increase productivity – Data centers with multiple Hyper-V physical hosts can service those systems in a controlled fashion, scheduling maintenance during regular business hours. Live migration makes it possible to keep VMs online, even during maintenance, increasing productivity for users and server administrators. Data centers can now also reduce power consumption by dynamically increasing consolidation ratios and powering off un-used physical hosts during lower demand times.
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