Configuration of the host server

Solution provider takeaway: In order to achieve performance optimization, it is essential that your client's host server is properly configured and their VMware ESX version is up-to-date. This chapter excerpt, from VMware ESX Essentials in the Virtual Data Center, will provide information on how to configure a host server and how to identity the important component areas for VMware ESX 3.5.

Download the .pdf of the chapter here.

Configuration of the Host Server

Virtualizing your infrastructure or even a small number of your physical servers can offer enormous benefits to your organization. But it is important to realize that virtualization can also negatively affect the performance of your server, operating system and/or the applications if not properly setup, configured or planned. Therefore, you should understand the trade-offs that occur at the hardware layer with virtualization and to make sure to properly configure the host server on a component-by-component basis. In this section, we will focus our optimization efforts on the physical host server including the virtualization platform chosen, its processor, memory, storage and its network.

TIP
Make sure you check all the installed hardware items in your host server against the most recent supported hardware compatibility list (HCL) from VMware for whatever version of ESX you are installing. Adding unsupported hardware components can cause performance problems, or worse.

Upgrade your Version of VMware ESX

If your environment is still operating with some earlier version of VMware ESX Server 2.x, now might be the time to start thinking about upgrading, or better yet migrating it to the latest version. In case your VMware sales representative hasn't told you yet, there are significant performance improvements that can be made by simply running the latest version of VMware ESX. By upgrading your environment to VI3 3.5, you not only gain out-of-the-box performance improvements, but you also get significant improvements in scalability, usability, hardware compatibility and a host of new features and benefits described throughout this book.

VMware has optimized several of the component areas in VMware VI3. Doing so allows organizations to see an increase in overall performance, and it also offers the ability to now virtualize high demanding and intensive workloads that might have been previously difficult to do.

With the latest version of VMware ESX, virtual machines can enjoy an increase in the number of virtual CPUs that can be assigned to them. Early versions of VMware ESX restricted virtual machines to a single-processor environment. Since then, VMware has created Virtual SMP technology to give virtual machines the ability to operate with multiple processors. With the latest version of VI3, virtual machines can now enjoy the freedom of using up to four virtual processors. ESX 3.5 now makes use of 32 logical processors on a single host, with experimental support of as many as 64 logical processors. And it can also take advantage of ACPI power saving mode to better handle the wasted cycles consumed by idle virtual machines. Virtual memory limitations have also been increased. Virtual machines can now enable Physical Address Extensions (PAE) to access up to 64GB of memory where the early limitations had been set at 3.6GB of memory for quite a number of years. The memory limit for VMware ESX host servers has also been increased to 256GB. ESX 3.5 has also improved its Non-uniform Memory Access (NUMA) scheduling algorithms which should greatly benefit the virtual machines running on NUMA platforms.

Virtual networking has also gone through a significant overhaul and refresh with the latest version of VI3. Improvements have been made with both the virtual network adapter and the virtual switch. Virtual adapters are capable of GigE speeds, the number of virtual switches has increased as did the number of ports available, and an additional load balancing method called port ID is also now offered. A new version of the VMXNET virtual device called Enhanced VMXNET is available, and it includes several new networking I/O enhancements such as support for TCP/IP Segmentation Offload (TSO) and jumbo frames. ESX 3.5 hosts now fully support 10 GigE NICs which offer huge performance improvements compared to traditional 100 Mb Ethernet cards. Experimental support for Intel I/O Acceleration Technology (I/OATv1) has also been added. If your system's chipset has this feature, you should be able to see improvements in your networking performance.

A number of architectural improvements were made to the ESX 3.5 storage subsystem. VI3 now supports Infiniband-based Host Channel Adapters (HCA). Instead of using NICs and Fibre Channel adapters, you can install Infiniband HCA adapters which would look like Fibre Channel adapters and Ethernet NICs to the virtual machines. VMFS-3 is a new version of the VMFS family of clustered file systems that offers enhanced performance and scalability over previous versions. Virtual machines are less dependent upon the Service Console and their user-level virtualization components can now run on any available processor core which gives the ability to scale up to 50% more virtual machines per host server.

Other features available in VI3 that enhance performance and scalability include VMware Distributed Resource Scheduler (DRS), Resource Pools, High Availability (HA), VMotion, Storage VMotion and VMware Consolidated Backup (VCB) to name but a few. These and other VI3 enhancements are discussed in more detail throughout this book.

About the book
VMware ESX Essentials in the Virtual Data Center details best practices for ESX and ESXi, guides you through performance optimization processes for installation and operation, uses diagrams to illustrate the architecture and background of ESX and covers the two most popular releases, 3.0 and 3.5.