SP1 for Windows Server 2008 R2 Requires Lots of New Hardware
SP1 for Windows Server 2008 R2 Requires Lots of New Hardware
At TechEd, held June 7 to 10 in New Orleans, Microsoft unveiled the technical details and timing of the first service packs expected for the Windows Server 2008 R2 and Windows 7 operating systems, which could be of particular importance to companies investigating the use of VDI, or virtual desktop infrastructure.
During his keynote, Bob Muglia, president of Microsoft's Server and Tools Business, announced the timing-the first beta will be delivered by the end of July-while the technical details were expounded in a series of breakout sessions over the course of the conference.
As has often been the case in the last several years, the service packs for the latest versions of Microsoft's client and server are contained in the same download package (for 64-bit, at least, as there are no 32-bit 2008 R2 editions). But while Service Pack 1 for Windows 7 won't contain much in the way of new features, instead rolling up those patches and fixes already delivered via Windows Update along with an updated Remote Desktop client, SP1 for Windows Server 2008 R2 will have a couple of significant enhancements.
The two most important new features for Windows Server 2008 R2, Dynamic Memory and RemoteFX, focus on enhancing both the back-end performance and end-user experience of virtualization workloads. Those running Remote Desktop Services servers or Microsoft's VDI services could immediately benefit from those features (particularly the former), while those running 2008 R2 for other roles will only get rolled-up hotfixes and some incremental improvements.
Dynamic Memory is a Hyper-V enhancement allowing the administrator to set a memory range on a virtual machine to improve VM density, allowing customers to squeeze the maximum performance out of host memory without paging to disk. Administrators define the low and high thresholds of memory for a VM, and the host and VM work together to assign memory to clients dynamically as needed for the client workload. So a VM with a base of 1GB of memory may only need that amount for basic operation, but will request more from the host when it starts a memory-intensive operation (opening a big Excel spreadsheet, perhaps.) Although the host pool of memory is shared between VMs, Microsoft claims it is done in a secure manner that does not provide the chance to perform memory reads across VMs.
Administrators can also configure a memory buffer on a per-VM basis, configuring Hyper-V to hold back a percentage of memory and not let it be used in other instances. Administrators can also set memory priority per VM, giving an order of precedence for those occasions when the virtual clients' needs exceed available system resources.
Although Dynamic Memory could have benefits for virtual instances of either Windows client or server, Microsoft representatives expressed the belief that virtual client instances-which have a greater variance in memory needs over time and workload-will likely be the biggest beneficiary of the feature. Servers, in their estimation, typically have more predictable memory needs.
Guest machines must be enlightened to support Dynamic Memory, however. At the start, the feature will only be available for Windows Server 2003 and 2008 (Standard, Enterprise and Datacenter editions in either 32-bit or 64-bit), and Windows Server 2008 R2 (64-bit, all editions). Also supported are the Enterprise and Ultimate SKUs of Windows Vista and Windows 7 clients (32-bit and 64-bit), but not the Business/Professional editions.
RemoteFX Relies on Servers with GPUs
RemoteFX, meanwhile, promises users a much richer client experience over VDI than was previously possible. RemoteFX, a byproduct of Microsoft's 2008 acquisition of Calista Technologies, delivers three-dimensional graphics rendering for Windows 7 virtual desktops, allowing users to take advantage of Aero desktop features, watch high-definition video and use 3D-intensive applications. RemoteFX also adds support for a wider range of client-connected USB devices, such as multifunction printers/scanners and unified communications devices such as headsets or Webcams.
The new graphics capabilities delivered via RemoteFX will likely not be realized by customers in the near term, as the feature requires a number of hardware and software enhancements on both the virtual server and client endpoints.
First of all, RemoteFX requires that host servers have a GPU installed. Graphics rendering for all virtual clients happens on the server host, with the server GPU being exposed to the guest operating system via a virtual GPU driver. RemoteFX time-slices the server's GPU to share across multiple Windows 7 remote or virtual sessions. Rendered data is sampled, then tightly compressed using a proprietary codec and delivered as a bit map over the network back to the virtual client via RDP. Compression at the server may be done in software (with work done by both GPU and CPU) or in hardware, if the hardware has an accelerating ASIC (application-specific integrated circuit) on board.
Microsoft claims RemoteFX uses intelligent screen capture to sample only detected changes, rather than the whole image over and over, but bandwidth usage is still enough to make the feature usable only over LANs. RemoteFX will send more frames on really fast networks, though. Administrators will be given centralized control over the maximum resolution and number of monitors supported on virtual clients, allowing some predictability in network capacity planning when using RemoteFX. Performance planning and deployment guides should be available by the SP1 RTM timeframe.
During a breakout session about RemoteFX, Justin Graham, senior product manager in the Windows Server Group, acknowledged that no one currently has GPUs in their servers (in a show of hands of the audience, only one member reported using GPUs in a server.) Graham said Microsoft wanted to deliver RemoteFX as soon as possible, in order to allow its customers time to adjust to, plan for and adopt the new hardware requirements for RemoteFX. And for its hardware partners to deliver those technologies in the first place so customers can buy them.
According to Microsoft's recommendations, each server in a RemoteFX-enabled VDI pool needs its own GPU (or an external GPU appliance can be used) to ensure RemoteFX operation as VMs migrate between hosts. Identical GPUs are needed if VM migration is a requirement.
RemoteFX is intended for new VDI deployments due to the increased hardware demands, which will require new servers in most cases. Customers should also account for the additional heat and power complexities that may arise with the use of server GPUs. Fortunately, Microsoft claims, RemoteFX is GPU-hardware-agnostic, so ATI, Nvidia and Intel GPUs could be equally effective.
Server-side graphics processing could be beneficial for low-horsepower clients such as netbooks or thin clients that lack higher-end graphics cards. Of course, the endpoints will need to support RemoteFX as well. For Windows 7-based endpoints, SP1 delivers a new Remote Desktop client (Version 7.1) that adds this support, and there should be updated clients available for Vista and Windows XP SP3 as well. Thin clients will likely need to be swapped out for newer models that support the RemoteFX codec on an ASIC, however.
Microsoft System Center users should be aware than these new features will not immediately be configurable through Virtual Machine Manager, although Microsoft officials said they expect support to be added soon after launch.
For non-Hyper-V or VDI customers, SP1 adds a few other new features. For instance, improvements to Active Directory increase the maximum number of connections, helping performance particularly in networks with high latency. Also with SP1, DirectAccess adds support for 6to4 and ISATAP addresses when used with Microsoft's Network Load Balancing.
Interestingly, I learned from Bill Laing, corporate vice president of Microsoft's Windows Server and Solutions division, that DirectAccess wasn't immediately appealing to the anticipated audience. Laing said, "We thought DirectAccess was pretty much an enterprise feature, but it's actually been small and medium businesses that love it most."
When I asked whether these customers were tightening security and access controls via NAP (Network Access Protection), he responded, "No, they are keeping it pretty simple."
For more information about the changes coming in SP1 and deeper dives into the underlying technologies, check out these TechEd sessions (VIR304, VIR305, WSV307, WSV309, WSV13INT).