Since I started on the topic of consolidation and virtualization, here’s my take on server virtualization and the 8 things you should be aware of:
- According to Gartner, server virtualization aren’t as common as we all think it is. Only about 16% of workloads are currently running in VM (virtual machines). They estimated that this number will reach 50% by end of 2012. And the fastest growing market today is the small & medium enterprises (SME) – estimating the SMEs will surpass global 500 large enterprises in adoption very soon! Currently, the two largest market leaders are VMware and Microsoft. However, it is estimated that by 2012, at least 25% of the virtual machine installed base in enterprises will be Microsoft Hyper-V.
- The market landscape for x86 server virtualization are actually much more than just VMware. In the market today, the available technology products are Microsoft Hyper-V, Citrix Xen-based virtualization product, RedHat KVM virtualization, Parallels (niche with Virtuozzo containers), Oracle VM, and Novell’s SUSE Linux-Xen based product.
- Contrary to popular belief, server virtualization isn’t just about saving money. Enterprises would often start off with the intention to save money, but subsequently will begin to realize that they have achieved greater agility, ease of use, DR capability, etc. All of which are valuable benefits (besides saving money). However, be cautious of the downside of server virtualization. Software licensing, especially for COTS software may increase depending on the licensing scheme the vendors applies. For example, if the software is licensed by number of installed instance (regardless of physical or virtual), or licensed by number of fixed or concurrent users, then there isn’t much to worry about. But if the software is licensed by processor, where you incur a cost for each processor or a tiered or different cost based upon the number of processors on the server, then depending on the verbiage of the license agreement, your licensing cost may apply to the overall number of physical processors installed on the computer or it might apply to number of virtual processors. If it is the case of the former, you will get a shock!
- Depending on the use case of the server virtualization workload being deployed, it is necessary to evaluate and assess whether the ISV or software vendor will support their application running on a virtual machine. When virtual machines are planned on being used in a production environment, it is wise to find out if the intended production applications will be supported for production use by the server virtualization platform vendor or the ISV of the application. Some server virtualization platform vendors may not fully support certain enterprise-class applications hosted with their server virtualization platform in a production environment. It is very important to try to reduce the amount of risk and to know exactly what support options are available when the need arises, especially for production systems.
- After all the homework, now comes the part about choosing the right virtualization technology – If you’re looking at virtualizing >200 workloads, have low tolerance for downtime, expect a matured product, rich features, ability to move workloads from one physical machine to another on the fly, great management capability for few hundreds or thousands of VMs, I/O performance, with a mix of OS environment, then VMware vSphere 4 would likely be your choice. If your OS environment are mostly Microsoft Windows and you don’t intend to virtualize more than 100 workloads, then Microsoft Hyper-V/SCVMM R2 can be considered. If your environment are heavy Linux, other options such as RedHat RHEV or Citrix XenServer can be considered too. For environments with lots of Oracle apps, databases and these are managed separately, not critical to be shared, then Oracle VM is ideal.
- Virtualization will bring in new changes in your day-to-day operations. Do expect higher demand of capacity and VMs, a more transient usage, and resource hogging. Capacity needs to be managed – establish policies and processes (approvals, quotas, chargeback, service reporting, etc.) as controls. Performance management and service level management becomes more complicated as dependencies and availability blurs into virtual environments. Be mindful of VM placement, VM density, the performance overhead of the hypervisor, VM resource competition, etc. Need to evolve and maintain descriptive metadata to manage these. At the same time, need to initiate a mindset change with the business users to shift from project-based and BU funded assets into a usage-based service delivery model (this is where you, as the IT service provider, in your organization accounts for all assets, usage, and charges the BU for the services).
- Virtualization, depending on the technology you adopt, can possibly introduce a new platform or layer which must be managed as with any other configuration item, i.e. be patched, updated, included in configuration management, etc. Fail to neglect this new platform or layer, and your operations and service levels will fail you.
- Network performance issues could likely arise in server virtualization because of the many virtual machines sharing a single or few network adapter(s). So, for situation where a Fast Ethernet (10/100) network is the only available option, then it becomes a potential bottleneck. Gigabit Ethernet (10/100/1000) is preferred in a virtualized environment, but in order to capitalize and take advantage of the increased bandwidth, the network adapter on the server, cabling, and network switches must all support Gigabit Ethernet. Just like VM density of a physical server, there are also decisions that needs to be taken on how many virtual machines and which virtual machines can or should share the same network interface.
I’ll stop at 8, being an auspicious number for the coming of Spring in the Chinese New Year. Wishing all a great, rewarding and prosperous new Year ahead!
Tags: Architecture, Availability, Consolidation, Density, Network, Operations, Service Management, software, Technology, Virtualization