Stacking up the hypervisors

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This article appeared in the May, 2010 issue of CRN magazine.

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Stacking up the hypervisors

AAny decision by a reseller to select a virtualisation solution and its hypervisor begins with understanding what their customer hopes to get out of it.

Many users are still far from deploying private or public clouds. But virtualisation is no longer a buzz word: it has proven-use cases in organisations of all sizes such as for consolidation, disaster recovery and high availability.

So ask your customers, do they just want to consolidate their servers? Are they interested in high availability for their business-critical applications? Or do they want to pursue a legacy environment?

And then what affinity do they have with an environment? The operating system could start to diminish as the central element of control in a stack as it moves into the cloud but today, at least, it's still extremely relevant.

Not just for operational practices but also in terms of applications and workloads where there is usually a binding with the operating system. 

Does your customer have a Windows, Linux or mixed shop, for instance? Or does it need to run Solaris or Netware? All those hypervisors have different levels of suitability and affinity for those operating environments.

If you're dealing with purely a Linux shop and Windows is an afterthought then Microsoft would also be an afterthought for your customer.

So interrogate them to discover what is the value proposition of the hypervisor and virtualisation you are considering for them and their technical affinity to deal with it?

Think about whether you are fighting the "air war" or the "ground war". The deeper you go into your customer's organisation the better you understand what's used on the ground. The higher you go in the company, say up to the office of the CIO, the customer tends to be more susceptible to marketing and what they read in the in-flight magazine ("air war").

At the executive level you often find close ties with particular vendors and their products, so that's where loyalty comes in strongly. You may not read much in the press about the Oracle hypervisor based on the open-source Xen but Oracle's relationships with executives in user organisations is very strong.

VMware is getting publicity with technical experts for its software and is perceived as the leading solution, but these battles may be fought at higher management levels.

A value-added reseller should tread carefully in such areas to avoid embroilment in political battles in their customers' organisations.

You're not likely to get into political fire fights for the relative benefits of an obscure feature; virtualisation is now elevated to have strategic relevance to the business. In these cases, the battles will be fought on all kinds of factors, technical and political.

Closeup: The hypervisors
Open source
Xen is the leading open-source hypervisor. If you cared about open source and access to the source code or cared about a diverse base of suppliers, this is your likely starting point. Sometimes people like the cost, the control, the fact you can contribute and leverage the development and sometimes the diversity, where it's an open market and you won't be locked into one vendor.

It was initially offered by many companies including major Linux distributors such as Red Hat and Novel, Virtual Iron (bought by Oracle), Oracle and Citrix but there's been some consolidation in the market.  Red Hat and Novell steered away from Xen and committed to rival open-source KVM while Oracle-Sun-Virtual Iron and Citrix stuck with it.

The Linux players still have to support their own operating system distros - the main part of their businesses - so that's what they wanted to focus on. The development effort around Xen didn't leverage the development of their OS products as much as they liked. Their mainline Linux development diverged from the hypervisor too much and they wanted to bring that back together.

KVM makes more use of operating system developments than Xen, which is more focused on the hypervisor. So it's useful for Oracle where the operating system is a secondary business.
If your interest in a pure hypervisor is more important than Linux per se, Xen is more relevant.

But if you're more interested in Linux, that's where KVM comes to bear.

My sense is that for the things that count, both the open-source hypervisors perform about the same as each other. They each have virtual SMP (symmetric multi-processing) and live migration to move virtual machines from one host to another without shutting them down.

Microsoft Hyper-V R2
People familiar with Windows and hesitant to bring in additional software will find Hyper-V very attractive. It's a low risk option because you don't have to learn a new interface or worry about hardware compatibility as you do with VMware. Even if your customer feels Microsoft is not delivering fast enough, they can bring in VMware later so there's no urgency.

And Microsoft has done a pretty good job of bringing in what the market needs such as live migration, which is mostly a "check-box requirement". That will go a long way to neutralising the perception that Microsoft is really far behind its competitors.

Microsoft has been very good in integrating management of the Windows OS with the virtualisation layer. That can be very important because VMware has fantastic tools for managing the virtual part of the infrastructure but its tools are limited in how they control the OS and workloads in the OS.

That's where Microsoft has a real strength - it gives the IT manager control of the entire software stack, which is important when you get serious about managing virtualisation workloads such as bottlenecks and for reliability.

Virtualisation is becoming such a strategic issue especially since it's no longer about virtualisationbut the doorstep to the cloud; it would be naive to think that this is just a tactical feature to make sure Microsoft has its toe in the water. 

Microsoft compares virtualisation to another feature of the OS such as TCP/IP at the start of the internet, when there were stacks from a variety of providers, then they built it into Windows and it became a standard feature. Virtualisation, because of its heterogeneity and separate control of hardware from control of applications, drives a wedge into a layer of control once unified.

This is an area rife with opportunity for resellers who can take advantage of what Microsoft has done with manageability through the Pro Pack.

For instance, actions can be triggered based on set conditions such as migrating a virtual machine between data centres based on the cost of power at peak loads. Much of this was in earlier versions of the software but with the addition of live migration the power of Microsoft's management comes into focus.

Key features
Cluster Shared Volume: Based on Microsoft's file system technology so it is more compatible with Microsoft file system tools than VMware's equivalent, VMFS. It still has some rough edges but over time you will have a lot more affinity with CSV (clustering) and Microsoft storage infrastructure.

A lot of the mass solutions are oriented around Microsoft storage infrastructure and that could become a strength for them because they can create an affinity with their dominant NTFS.

Processor Compatibility Mode: When you move virtual machines from one host to another you have to be careful because they have to run on compatible processors. Microsoft has mechanisms to deal with that so you can define virtual machines to be a little more generic in their expectations and that puts Microsoft a little ahead of VMware.

VMware vSphere 4.0
VMware has a vision for virtual infrastructure through its work with EMC and Cisco that shows crisply how to get to the cloud. They can show connections between the private cloud today and how that extends to a public cloud, so they have the most complete vision for infrastructure as a service. It will resonate most with users that care deeply about this.

A lot will come down to money and individual agreements that Microsoft and VMware make with resellers for marketing funds, and that's a ground war.

VMware understands the challenge there. They told us last year they were very focused on this and building relationships with partners, and that's a work in progress. That's an area where Microsoft has a huge advantage because its base is so huge and well-established.

Key features
Fault Tolerance: Running two identical hosts in lockstep; each server mirrors the other, each instruction is run in parallel.

Data Recovery: A centralised management interface for performing disk-based backup and recovery of virtual machine storage, optimised to protect data in SMB environments. .

Network Distributed Switch: A framework for managing virtual networks across a data centre from a central interface, allowing administrators to monitor and maintain the security of virtual machines as they move between physical servers. 

Host Profiles: A quick and easy provisioning mechanism to automate the configuration of vSphere hosts by registering the resources, networks, storage and security settings that they need.

Hot Add: The ability to add resources to a running virtual machine online without shutting it down so it can be done during normal office hours.

vStorage Thin Provisioning: It's getting a lot of interest among storage users because it allows you to define how much storage a virtual machine will have available, but you don't have to provide it up front.

vShield Zones: It's a security mechanism so you can take subnets and maintain integrity at the level of the virtual subnetworks.

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