At VMworld 2013 in San Francisco, VMware announced the release of vSphere 5.5. As its 5.5 version number suggests, the new vSphere release is more of an evolutionary update than a revolutionary release. Many of the enhancements focus on extending scalability and catching up in those areas where Microsoft Windows Server 2012 Hyper-V has leap-frogged it. Here are the top 10 features in VMware vSphere 5.5.

1. Increased Maximum RAM and vCPUs per Host—In his VMworld keynote address, VMware CEO Pat Gelsinger referred to vSphere 5.5 as the 2X release because VMware essentially doubles the scalability of vSphere. The maximum supported RAM per host has been increased from 2TB to 4TB. Likewise, the number of logical CPUs supported per host has increased from 160 to 320. These improvements essentially put vSphere 5.5 back on par with Hyper-V.

2. Increased vCPUs per Host —Another closely related scalability enhancement is the increased number of vCPUs supported per host; vSphere 5.5 supports up to 4,096 vCPUs per host, whereas the older version topped out at 2,048.

3. Increased NUMA Support—For virtualized workloads, physical memory is probably the most important resource. Most new servers provide non-uniform memory access (NUMA) support. NUMA is designed to improve performance by assigning memory on a per-processor basis. Each block of memory assigned to a processor is known as a NUMA node. A CPU can access the memory in its local NUMA node more quickly than it can access a non-local NUMA node. In vSphere 5.5, the support for NUMA nodes is increased from 8 to 16 nodes.

4. Support for CPU C-States—In vSphere 5.1, VMware provided support for CPUs' enhanced performance state (P-state), allowing processors to run at lower frequency and voltage settings during periods of low resource utilization, while increasing those settings during periods of high utilization. Now, vSphere 5.5 can use the deep processor power state (C-state) to minimize the power consumed by idle CPUs during periods of inactivity.

5. Scalability Enhancements for the Free vSphere Hypervisor—Another important change, especially for small-to-midsized businesses (SMBs), is memory support enhancements to the free vSphere hypervisor. With vSphere 5.5, the free vSphere hypervisor no longer has any physical memory limitations; the older version was limited to 32GB of host RAM.

6. Support for 62 TB VMDK Files—The increase in maximum virtual machine disk (VMDK) size is a welcome enhancement of vSphere 5.5. Previous releases of vSphere limited the VMDK size to 2TB; vSphere 5.5 pushes the maximum VMDK size to 62TB for both VMFS-5 and NFS.

7. Support for Hot-Pluggable PCIe SSD Drives—As prices continue to drop, high-performance solid state disk (SSD) drives are becoming more prevalent in today’s data centers. Previous releases of vSphere have supported hot-pluggable SATA and SAS drives. The new release supports hot-pluggable SSD drives, as well.

8. Improved Networking Performance—The vSphere 5.5 release provides improved network performance with support for 40GB NICs. Another networking enhancement provides support for 16GB end-to-end (E2E) Fibre Channel connections. With the previous release, the host-to-switch connection could run at 16GB but the switch-to-array connection was limited to 8GB. The vSphere 5.5 release now supports full 16GB E2E Fibre Channel connectivity.

9. Expanded vGPU Support—Previously, vSphere 5.1 introduced support for hardware-accelerated 3D graphics using vGPUs inside of a virtual machine (VM), but this support was limited to NVIDIA GPUs. Now, vSphere 5.5 adds support for AMD and Intel GPUs, as well as the ability to use vMotion to move a VM between GPU vendors. However, if the vGPU is configured to use hardware rendering, the GPU must exist in the destination host; otherwise, the vMotion procedure will fail.

10. App HA—One of the other major enhancements in vSphere 5.5 is the new App HA feature. App HA extends VMware’s operations monitoring capabilities to a number of business-critical applications. The new App HA can monitor SQL Server 2012, 2008 R2, 2008, and 2005; as well as IIS 8.0, 7.0, and 6.0; Tomcat 7.0 and 6.0; and Apache HTTP Server 2.2, 2.0, and 1.3.