September 24, 2013 | Written by: Bhanu Tholeti
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One of the best ways to determine which hypervisor meets your needs is to compare their performance metrics. These include CPU overhead, support for virtual processors and amount of maximum host and guest memory. But metrics alone should not determine your choice. In addition to the capabilities of the hypervisor, you must also verify the guest operating systems that each hypervisor supports.
If you are running heterogeneous systems in your service network, then you must select the hypervisor that has support for the operating systems you currently run. If you run a homogeneous network based on Windows or Linux, then support for a smaller number of guest operating systems might fit your needs.
All hypervisors are not made equal, but they all offer similar features. Understanding the features they have as well as the guest operating systems each supports is an essential aspect of any hardware virtualization hypervisor selection process. Matching this data to your organization’s requirements will be at the core of the decision you make.
The following factors should be examined before choosing a suitable hypervisor:
- Virtual machine performance: Virtual systems should meet or exceed the performance of their physical counterparts, at least in relation to the applications within each server. Everything beyond meeting this benchmark is profit. Ideally, you want each hypervisor to optimize resources on the fly to maximize performance for each virtual machine. The question is how much you might be willing to pay for this optimization. The size or mission-criticality your project generally determines the value of this optimization.
- Memory management: Look for support for hardware-assisted memory virtualization. Memory overcommit and large page table support in the VM guest and hypervisor are preferred features; memory page sharing is an optional bonus feature you might want to consider.
- High availability: Each major vendor has its own high availability solution and the way each achieves it may be wildly different, ranging from very complex to minimalist approaches. Understanding both the disaster prevention and disaster recovery methods for each system is critical. You should never bring any virtual machine online without fully knowing the protection and recovery mechanisms in place.
- Live migration: Live migration is extremely important for users; along with support for live migration across different platforms and the capability to simultaneously live migrate two or more VMs, you need to carefully consider what the individual hypervisor offers in this area.
- Networking, storage, and security: In networking, hypervisors should support network interface cards (NICs) teaming and load balancing, Unicast isolation, and support for the standard (802.1Q) virtual local area network (VLAN) trunking. Each hypervisor should also support iSCSI- and Fibre Channel-networked storage and enterprise data protection software support with some preferences for tools and APIs, Fibre Channel over Ethernet (FCoE), and virtual disk multi-hypervisor compatibility.
- Management features: Look for such management features as Simple Network Management Protocol (SNMP) trap capabilities, integration with other management software, and fault tolerance of the management server — these features are invaluable to a hypervisor.
A few suggestions…
Now I don’t want to influence your choice of hypervisor (after all, your needs and requirements are unique), but here are a few general suggestions from my experience with implementation of hypervisors for cloud-based workloads:
- For UNIX®-based workloads, business-critical applications comprised of heavy transactions where performance is the paramount requirement, the PowerVM hypervisor is capable of handling that sort of load.
- If you’re running business-critical applications on System X (x86 servers for Windows and Linux), VMware ESX works quite well.
You can even try out some of the freeware VMs like Xen and KVM.
If you want to suggest any other topics for me to cover or if you’d like to continue the discussion, leave a comment below.