In the not so distant past, VMware held a long and commanding lead in the server virtualization space, offering core features that were simply unmatched by the competition. In the past few years, however, competition in virtualization has been fierce, the competitors have drawn near, and VMware has been left with fewer ways to distinguish itself.
The competition may have grown over the years, and VMware may not enjoy quite as large a lead as it once did — but it still enjoys a lead. With useful improvements to a number of key features, as well as the bundling of functions such as backup and recovery that were previously available separately, vSphere 6 is a worthy addition to the vSphere line. That said, some of the major advances in this version, such as long-distance vMotion, will matter most to larger vSphere shops.
Big changes in vSphere 6
The big changes in vSphere 6 revolve around expanded resource limits, enhanced vMotion capabilities, a more complete version of the Linux-based vCenter Server Appliance, storage offloading, and enhancements to the Web client. In addition, VMware has bundled extra technologies into vSphere 6, such as the vCenter Director content library that is used to store ISO images, templates, scripts, OVF files, and other elements, and to automatically distribute them across multiple vCenter servers. The Data Protection Advanced backup and recovery tools are now included as well.
VMware vSphere 6 offers advances in the previously existing Fault Tolerance feature. Fault Tolerance is the technology by which a single VM can have presence on multiple physical servers simultaneously. Should the physical server running the active instance fail, the secondary instance is immediately activated. Without Fault Tolerance, the VM could be automatically restarted on another host, but would require time to detect the failure and boot on the new host. With Fault Tolerance, that step is avoided.
In previous versions of vSphere, Fault Tolerance supported only a single vCPU per VM and four fault-tolerant VMs per host. In vSphere 6, the limits are now four vCPUs per VM and either eight vCPUs or four VMs per host.
The vMotion improvements will be more germane to those with multiple data centers spread over wide geographic areas. Prior to vSphere 6, live-migrating VMs over large distances was problematic and required high bandwidth and low-latency connections to succeed. In vSphere 6, the network tolerances have been extended, and vMotions can now be completed over links with 100ms latency or less, requiring 250 megabits of bandwidth per vMotion.
In addition, VMs can be vMotioned between vCenter servers, and with a proper underlying infrastructure, vMotions can be completed without common shared storage. There are restrictions that come with these expanded capabilities, mostly in the form of proper network layouts at each side to allow for proper communication of the VMs on each network.
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