Windows Server 2012
by Kay Ewbank
The benefits you can achieve by upgrading to the most recent version of Microsoft Windows Server.
HardCopy Issue: 59 | Published: February 1, 2013
When a new version of any operating system is released, it can be difficult to know when to bite the bullet and upgrade. This is particularly true of a server operating system. If your current servers are running reasonably well and your users are reasonably happy, you have to be faced with pretty strong evidence of major advantages before you are going to be prepared to face the inevitable upheaval that a migration involves. However Windows Server 2012 does have improvements that can save resources and money.
Of course, you may already be fully occupied migrating Windows XP desktops in advance of the removal of support in Spring 2014, but even in those circumstances, take a careful look at Server 2012 as the changes in licensing and support for virtualisation could save you substantial amounts in money and infrastructure.
Ask people who have already made the move to Windows Server 2012 what the best thing about it is and its provisions for virtualisation will undoubtedly come top of the list. Windows virtualisation has been improving in recent versions but has still been catching up with VMware. The version of Hyper-V in Windows Server 2012 has been dramatically improved with support for up to 64 processors and 1TB of memory for each virtual machine, alongside up to 16TB virtual disk space per virtual hard disk. Windows Server 2012 also supports up to 320 logical hardware processors and 4TB of RAM for each host.
Efficiency gains for hosting provider Fasthosts
Fasthosts is a British hosting provider serving more than 400,000 customer from facilities that house more than 6,500 dedicated servers. Lee Harrison, Lead Virtualization and Storage Engineer on the Infrastructure Team at Fasthosts, was particularly impressed by the new Hyper-V technology that comes with Windows Server 2012: “The more we heard about it, the more excited I became. The new version of Hyper-V offered us the scalability and flexibility that we needed.”
For Harrison, Hyper-V Replica is a highlight: “Someone really thought out this feature. It’s a simple and elegant solution for disaster recovery.” Windows Server 2012 also opens up business opportunities for Fasthosts, as Chief Technology Officer Jonathon Royle explains: “There’s a real opportunity to ‘productise’ the Hyper-V Replica feature, for example, to offer a ‘replication as a service’ offering.”
Overall, Fasthosts is confident that this new version of Windows Server will bring considerable benefits. “We are still evaluating the savings in a production environment, but I am confident that we will lower the cost to manage our platform, and we will have fewer custom management tools to maintain,” says Royle. “By using Windows Server 2012 and System Center 2012, we should be able to support a 25 per cent growth in business without growing our data centre staff.”
The raising of these limits makes it possible to virtualise even machines that are heavily used and in need of a lot of computing power. In addition, the ability to virtualise machines can reduce licensing costs.
The improvements to Hyper-V go further than hardware support, with new features including multi-tenancy, shared storage resource pools, and network virtualisation. It also has much improved replica support, so you can set up a virtual machine that is resilient to hardware failure, replicating it from one Hyper-V host at a primary site to another Hyper-V host at the replica site.
The multi-tenancy support is particularly important because using it with the shared storage lets you set up your own private cloud, giving you the benefits of a cloud service without exposing your data to the outside world.
The support in Windows Server 2012 for multi-tenancy means you can run a single instance of software on the server for multiple client organisations or departments. The server software virtually partitions its data and configuration, and the clients each have their own customised instance of the virtual application.
Shared-nothing Live Migration
The multi-tenancy support is backed up with ‘shared-nothing’ live migration so you can move virtual machines as well as data. Virtual machines can be moved from one physical server with direct attached storage to another physical server, either in the same cluster of servers or between clusters. This flexibility allows network managers to minimise or completely avoid down-time for virtual machines. Combined with more flexible ways to manage storage, this can improve the experience users have of network availability.
Expensive SANs (Storage Area Network) make shared storage easy but have been out of reach for many smaller businesses. Windows Server 2012 lets you achieve the same results using less expensive off-the-shelf disk drives.
Storage Spaces let you create a shared pool of hard disks that can be treated as virtual storage, and you can even set the virtual drive to be larger than the actual physical space available (if you run out of space you add more to the existing pool). The pooled drives can be made more resilient by mirroring the drives, or by using parity striping where data is split into blocks and then spread across partitions on different disks.
Windows Server 2012 also supports network virtualisation. This means you can set up apparently separate networks on a shared network infrastructure without needing to use virtual local networks (VLANs). What happens is that you assign a virtual network identifier that says which virtual network a machine belongs to. Other machines on the same physical network can be assigned to other virtual networks, and the separate virtual networks are invisible to each other. You can move virtual machines as needed without changing their virtual network assignments, and you can even move an entire virtual network onto another physical network without changing IP addresses, so the users see no change and can continue working uninterrupted.
This technique overcomes the traditional problem of having a rigid VLAN where virtual machines can either be fighting for scarce resources, or where the physical infrastructure is underused.
This is an area where Microsoft has worked hard to improve the facilities in Windows Server 2012. Files are segmented into small variable sized data chunks of between 32KB and 128KB, and where multiple copies of data are found, duplicates are removed. The single chunk that is kept is then compressed. Deduplication can be carried out on NTFS volumes and is tightly integrated with BranchCache – the system whereby content from file servers on a wide area network (WAN) can be cached on computers at a local branch office.
The savings that can be achieved using data deduplication can be considerable. Chris Losch reckons the London Borough of Newham has seen individual reductions on file servers of between 18 and 64 per cent in space used, allowing the council to allocate one terabyte in every four to other uses. Some of the machines he manages are leased which has allowed the IT department to avoid step costs where the leasing cost increases as limits are reached.
Take backups into consideration and the storage reduction because of data deduplication is even greater. If you need to retain data for a specific length of time, then the reduction is multiplied by each backup image. Having less data also means that the time required for the backup window is lower, and a final benefit comes from the fact that reducing the number of file servers needed also saves power.
Many of the improvements to Windows Server 2012 are designed to reduce the upheavals involved when making changes. Cluster-Aware Updating (CAU) is a good example of this. Using CAU, you can update clustered servers while keeping the servers on the cluster available. CAU transparently takes one node of the cluster offline, installs the updates, performs a restart if necessary, brings the node back online, and then moves on to the next.
The smaller business view
Sometimes when you look at new software, it seems that everything was designed with large enterprises in mind. However Windows Server 2012 offers real advantages for smaller companies, too.
London Boroughs set up private cloud
Chris Losch, Enterprise Architect at the London Boroughs of Newham and Havering, cites the virtualisation support in Windows Server 2012 as the main benefit: “In Windows Server 2008 there were limitations on the number of processors, and it was difficult to maintain separate security when using machines with multiple tenants. In 2012 those limitations have effectively gone; the current limits are higher than we ever anticipate using, and that means we can virtualise more of the machines with heavy computing requirements.”
Multi-tenant separation of clients has also been a benefit: “The new multi-tenant capabilities mean separate virtual machines really are separate from the viewpoint of security when running on the same hosts, and that means we can consolidate servers.” He continues: “By using the multi-tenancy features, along with storage pools and network virtualisation, we’ve been able to set up our own private cloud. We’ve also been able to reduce our disaster recovery costs by £30,000 per year by backing up systems such as databases and line of business apps to a second site using native replication.”
Losch reckons they have achieved a two-thirds reduction in the number of licences required, and a three-quarters reduction in overall licensing cost, as a result of upgrading.
For a start, you can use it to provide a more robust system, or at least a system that’s more available. The virtual machine support means users can continue working even if you move things around, while virtual machine replication and ‘shared nothing’ migration lets you move resources around without needing to be very technical, so cutting down on IT costs. The more robust storage in the form of the storage spaces feature means you can take cheap storage and group the individual components like a SAN. This shared storage is then available through the native network features without the cost overhead of a ‘real’ SAN.
Some of the features that Windows Server 2012 offers come under the heading of ‘light touch administration’. A good example of this is the addition of support for DHCP failover. You can set up two servers so that if the active DHCP server fails, the standby server automatically takes over. This means the users IP addresses just carry on working. It may seem a small improvement, but anyone who’s ever rushed around trying to get a system back online with users screaming that their machine can’t get onto the network will know just how good a change this is.
The need to plan
While Windows Server 2012 offers some real advantages, if you want to get the best out of it you need to plan what you’re doing and potentially re-design your network to maximise benefits. For example, if you want to use multi-tenancy in the virtual networking features, or if you want to make use of the ability to create a small SAN using shared storage, you can’t just upgrade and get those benefits. You need to design from the bottom up to make the features work.
This isn’t necessarily a problem, but you need to do the planning. For example, if you’re configuring a file server and want to use Windows Server 2012’s dynamic access control lists, you’ll soon discover that it’s a completely different way of working. The features are there, but you need to work out how you’re going to make the transition.