Windows Server 2008 R2, which released to manufacturing today, July 22nd, 2009, contains major functionality improvements in virtualization and networking over the previous version.
This afternoon, Microsoft has announced the Release to Manufacturing (RTM) of Windows Server 2008 R2, which incorporates many hundreds of bug and security fixes from the previous server version released in June of 2008, also includes significant enhancements in the areas of Virtualization and Networking. Windows Server 2008 R2, initially titled in early betas as "Windows Server 7" is to be marketed alongside Windows 7 client and shares the same core operating system improvements.
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As initially reported back in April when the Release Candidate of Windows Server 2008 R2 was made available, many of the improvements are centered around the Hyper-V class 1 hypervisor that ships with the product:
Hot Add/Removal of VM Storage: LUNs and File Systems available to Hyper-V can be removed and added to the system without rebooting the physical host.
VM Chimney/TCP Offload – TCP/IP traffic can be offloaded from a VM to a physical NIC instead of a virtual network, for network intensive apps that use large data transfers and pre-posted buffers. This reduces the burden on the CPU, and is fully supported by Hyper-V’s Live Migration. To use this feature, you need Chimney compatible hardware, which I believe is equivalent to Intel’s VT-D extensions in the newest Xeon chips.Virtual Machine Queuing (VMQ) — Network Interfaces can now have direct memory access (DMA) into the allocated RAM of a Virtual Machine. This allows the virtual NIC on the VM to appear as multiple NICs on the physical host. The primary benefit of this function is that the virtual host no longer has device DMA data in its own buffer, which results in a shorter path length for I/O and greater network performance gain.
Physical Boot from VHD file — While not specifically a Hyper-V feature, this allows a physical Windows 2008 R2 server to boot from a VHD file (Virtual Hard Disk format used by Hyper-V and Virtual PC) stored on a Windows Server’s NTFS volume.
ZDNet Gallery: Windows Server 2008 R2
Logical Processor Support -- Server 2008 R2 supports up to 64 logical processors per system in Hyper-V. This feature is provided for future scalability, as only two 64-bit x86 systems on the market, Unisys's ES7000 and IBM xSeries 3850M2 can actually run this many processor cores.
A summary of the processor scalability improvements in Windows Server 2008 R2.
384 VMs per Host -- Server 2008 R2 supports up to 384 VMs running concurrently per host system. Again, this is primarily a feature that has been added for future scalability as very large amounts of memory and processors would be required per host to actually achieve this.
Live Migration -- Server 2008 R2 includes Live Migration of Virtual Machines between running Hyper-V hosts as a built-in feature. This feature is fully accessible using the basic Server 2008 R2 product as well as with the upcoming free Hyper-V 2008 R2 Server. Live Migration is a separate add-on product for Hyper-V's main competitor, VMWare ESX, which is only available as part of a much more expensive vSphere 4 purchase. Hyper-V Live Migration is supported on up to 16 node clusters. In addition to Live Migration Hyper-V also supports high availability and fail over (guest restart/reboot) on the same amount of clustered nodes.
Clustered Shared Volumes: Clustered Shared Volumes, or CSV, provides a shared file system overlay on top of Windows 2008 R2's NTFS for multiple Hyper-V hosts to centrally store virtual machines. A CSV provides a consistent file namespace, much in the same way VMWare ESX uses VMFS-3 "datastores".
However, unlike a VMFS-3 datastore, which is limited to 2TB each, can only hold up to 256 VMs per volume (with a practical limitation of 32 per due to I/O constraints) and must use VMWare's proprietary multi-path I/O (MPIO) an NTFS CSV can be up to 256 terabytes in size, can use a variety of MPIO solutions including EMC PowerPath, and has no limitation on number of VMs per volume. CSV's will also directly integrate with existing Windows-based backup solutions and not require "Proxied" backups, such as with VMWare's Consolidated Backup for ESX.
Microsoft's Clustered Shared Volumes for Hyper-V have theoretical upper limits that vastly exceed that of VMWare's competing VMFS-3 clustered locking file system for vSphere 4.
Processor Compatibility Mode -- This is an an enhancement for the Live Migration function that enables VMs to be moved to hosts with different CPU versions across the same processor family (Intel to Intel and AMD to AMD). This abstracts the VM down to the lowest common denominator in terms of instruction sets available to the VM. The benefits of this feature allow greater flexibility in Hyper-V clusters and enables migration across a larger range of Hyper-V compatible hardware.
Core Parking -- This feature, aimed toward building greener datacenters, allows Hyper-V to put a host's processors to "sleep" on an individual basis if they are not currently being utilized.
Additional Networking Improvements -- in addition to the TCP offload, VM Queueing and VM chimney mentioned above, Server 2008 R2 now has full support for 10Gb Ethernet and provides support for Jumbo Frames on both Gigabit and 10Gb networks.
With the release of Windows Server 2008 R2, Microsoft will also releasing to manufacturing within 60 days System Center Virtual Machine Manager 2008 R2 (SCVMM). SCVMM 2008 R2 improves upon Hyper-V's native management interface by including the ability to (quickly) template and provision VMs for Server and virtual desktop deployments, as well as provide automated storage migration.
Unlike VMWare's storage migration feature, Storage vMotion, Microsoft has chosen not to use a "Live" storage migration approach with their Quick Storage Migration, which suspends VM activity for several minutes while the VMs are being moved, after which the VMs are resumed from suspend. Microsoft insists that this is to ensure referential integrity of the data being moved, and that the majority of large enterprise customers which they worked with to integrate this feature did not do storage migration during production hours.
Are you excited about the improved virtualization scalability in Windows Server 2008 R2? Talk Back and Let Me Know.