Preview "The cloud is a tectonic shift," said Microsoft's corporate vice president of server and cloud Bill Laing, introducing an in-depth press preview of Windows Server 8 and mixing metaphors with abandon.
In response to this cloudy earthquake, the company is declaring Server 8 to be a cloud-based operating system, though note that this is not about Azure – Microsoft's platform as a service – but instead focused on plain Windows Server running on virtual machines, either in private clouds at corporate data centres, or in public clouds hosted by Microsoft partners.
The main justification for Microsoft's cloud-based claim is in extensive improvements to Hyper-V, the Windows virtualization platform. There are also changes to Microsoft IIS Web Server that make it better suited to multi-tenancy.
Before taking a detailed look at these, though, consider this statement from Jeffrey Snover, Microsoft's lead architect for the Windows Server division: "We don't want management GUIs to run on servers – that's a bad thing."
Few would disagree, yet it was Microsoft that popularised the idea of GUIs (Graphical User Interfaces) on servers when it came out with Windows NT Server in 1993. It seems that the Unix guys, and later the Linux guys, were right after all. Now the company is trying to unwind history by persuading its customers to run Windows Server without a GUI.
Microsoft introduced Server Core, also without a GUI, as an option for Server 2008, so the idea is not entirely new. Server Core, as Microsoft admitted at Windows 8 briefing, is not widely adopted. There are issues with third-party software that expects a GUI, and some management operations are challenging on Server Core. Another problem is that a Server Core 2008 install cannot be converted to a GUI install; you have to wipe and start again.
In Windows 8 Server this changes. The operating system is more modular, and you can add or remove the GUI without reinstalling. There will now be three configurations:
- Server Core, which is Microsoft's recommendation;
- full server without the graphical shell – in other words, GUI applications still run, but there is no Explorer or Internet Explorer; and
- full server with the familiar GUI. Microsoft stated that this is now intended only for backward compatibility.
Microsoft still intends that you use graphical tools to manage the server, but these should run remotely. In keeping with this changed model, the new Server Manager is designed to manage multiple servers, rather than the box on which it is running.
The enabler for this change is PowerShell, which happens to be Snover's invention. PowerShell was originally launched as a command shell and scripting language, but is now called an automation engine. There are thousands of cmdlets and the idea is that any management task can be accomplished with a PowerShell script. Microsoft told us that tools like Server Manager are now lightweight GUIs wrapping PowerShell scripts. In some cases, the scripts are exposed so that you can perform a task once in the GUI, see what script was generated, and then repeat it as a script, perhaps with modification, or within a loop targeting multiple servers.
PowerShell also gains IntelliSense, which is a feature that auto-completes keywords as you type, and a workflow engine.
Now or never: Hyper-V hits version 3.0
"It is version 3.0 that is the winner," said Snover, introducing an extensive set of changes to Hyper-V. The improvements are needed, since more than half of Windows Server instances are now virtual, and the proportion will increase. A Hyper-V host can now have up to 160 logical processors and 2TB of RAM, while virtual machines (VMs) can have up to 32 virtual CPUs and 512GB RAM.
Hyper-V storage sees many changes. A new virtual disk format, VHDX, supports drives larger than 2TB and improves performance. Users with SANs (Storage Area Networks) will benefit from support for ODX (Offloaded Data Transfer), which lets you transfer data by sending an instruction to the SAN rather than reading and writing the actual data – thus delivering a remarkable performance improvement. Creating a fixed-size VHDX – which used to be a long operation – is near-instant with ODX. The feature also benefits live migration, where Hyper-V drives are moved while online.
Hyper-V VMs also get up to four virtual Fibre Channel HBAs (Host Bus Adapters), giving access to gigabit-speed storage networks from within the VM.
Live Migration and Live Storage Migration, where VMs or virtual drives are moved while remaining online, can now be done concurrently by a Hyper-V host. One goal is to be able to patch and reboot a host server without loss of service, by moving VMs elsewhere, updating, and then moving them back.