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.
The ESXi 6.0 hypervisor in vSphere 6 can handle up to 64 physical hosts per cluster, up from 32 hosts, and each instance can now support up to 480 CPUs, 12TB of RAM and 1,000 VMs. Each VM can now be run with up to 128 vCPUs and 4TB of RAM, with vNUMA hot-add memory capabilities.
VMware vCenter Server improvements
On the management side, the vCenter Server Appliance is now feature-complete, on par with its Windows counterpart. Previously, you could run the Linux-based vCenter Server Appliance and manage ESXi hosts, but some of the more advanced features (notably Update Manager) of the Windows-based vCenter Server were not available. As of vSphere 6, the appliance can handle all the tasks that a Windows installation can. This is significant news to those who prefer to not manage a Windows server to run vCenter.
Those who run vCenter Server on Windows will notice that the installation procedure is simplified, though it takes quite a while to complete. All of the moving parts that make up vCenter Server are installed in a single action now, including the new Platform Services Controller, which handles SSO, licensing and certificate management. vCenter Server can be deployed with all components on a single system, or it can be split across multiple systems with the Platform Services Controller and vCenter Server installed separately.
Both vCenter Server for Windows and the vCenter Server Appliance now use a local PostgreSQL database by default, though external Microsoft SQL Server and Oracle databases are also supported on Windows and Oracle databases on the appliance. The switch to PostgreSQL will be important to those running with local databases on earlier versions of vSphere due to the fact that the limitations of the previous Microsoft database are no longer present; thus, local databases can now support 1,000 hosts and 10,000 VMs.
A better Web UI
The first version of the vSphere Web Client was slow, incomplete, and not nearly as fluid as the Windows client, and many users simply refused to work with it. In vSphere 5.5, we saw improvements to the Web client, but it still wasn't quite to the level of the stand-alone client. In vSphere 6, further usability and speed improvements make the Web client more palatable, as does the addition of support for a broader range of client browsers and operating systems. The client integration tools that allow for important features like VM console access are now available for more platforms, including Mac OS X.
Users of the Web UI will note that it bears a stronger resemblance to the stand-alone client, including the recent tasks pane at the bottom that displays what actions have been taken within the infrastructure. Further, the context menus available via right-click are better laid out, and the overall navigation in the Web client is better than the previous iterations.
The success of the Web client is crucial to VMware. The company has been warning about the impending demise of the stand-alone client for several releases and currently stresses that using the stand-alone client will limit the functionality of vSphere to vSphere 5.0 levels. Features and enhancements from vSphere 5.5 onward are simply not available in the Windows client.
VMware Virtual Volumes
VMware introduces a new storage integration concept with vSphere 6 called Virtual Volumes. This is essentially tighter integration with SAN and NAS devices to manage storage operations at the virtual disk level. Virtual Volumes are designed to eliminate the need to carve out large numbers of LUNs or volumes for virtualization hosts and to offload storage-related operations to compatible arrays, with granularity at the virtual disk level.
This integration includes vSphere Storage Policy Based Management, which uses VMware's storage API to communicate with storage arrays and connects the administration of VMs and storage through to the vSphere UI. Thus, policies can be created and applied to VMs through vCenter while related functions are performed natively by the arrays.
VMware now includes vSphere Data Protection with vSphere Essentials Plus and higher editions of vSphere 6. This is a VM backup and recovery tool that was previously known as vSphere Data Protection Advanced, a separate option. This tool can be used to provide application-aware VM backup and restoration, including support for Microsoft SQL Server, Microsoft Exchange down to the mailbox level, and other popular databases and applications.
Up from vSphere 5.5
With vSphere 6, VMware offers a collection of welcome features that are now bundled in rather than separate products, advances a number of pre-existing features, and streamlines the installation process. The Web client may still cause more than a few grumbles from those who have been using the stand-alone client from the beginning, but it's significantly better than in previous iterations.
The advances in vMotion and other cross-site features are of limited use to shops not running multiple interconnected data centers with sufficient dedicated bandwidth to support those features. But as VMware increases the tolerances to lower bandwidth and higher latency, the viability of introducing such features grows.
There's no mistaking the fact that VMware continues to hold the leadership role in server virtualization, but as the feature sets of the top vendors continue to converge and competing solutions continue to get more robust, we may see more of this feature bundling and simplified licensing in the future. For now, vSphere 6 maintains its place as the cream of the crop.
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