So, you’ve gotten your feet wet with virtualization and you like it, but you need more capacity. Even with the current generation of hardware when you use Microsoft Virtual Server 2005 or VMware Server as your virtualization platform, you start to take a noticeable performance hit starting at around four to six virtual server guests, depending on the load of each guest and the configuration of the host server. If you need better performance/capacity out of your existing host, because of increased load, consider the VMware Infrastucture Starter package (which includes ESX Server) if you’re not ready to commit to full blown VMware Infrastructure Standard or Enterprise packages. The starter package will allow you to get up to speed with the ESX hypervisor without a significant up-front investment.
The starter package does have some limitations, one of biggest being 8GB of memory on the host using only locally attached storage. Of course you won’t get all of the high availability features of the Enterprise package either. But the starter package will give you significantly better performance and higher consolidation rates than Virtual Server 2005 or VMware Server. The performance hit is significantly smaller with VMware Infrastructure. You might see a performance hit of 10 percent to 15 percent with Virtual Server 2005 or VMware Server when running a guest, but using VMware Infrastructure the performance hit is 7 percent or less. This translates to better performance for each guest running under VMware Infrastructure, and higher consolidation rates. We typically see eight to twelve guests on a host with dual quad-core processors. Of course, you’ll probably run into the memory limit of 8GB with VMware Starter at around six guests, depending on each guest’s memory requirements. VMware Infrastructure by itself takes approximately 600MB of memory leaving 7.4GB of memory for virtual server guests. Boot times are impressive with VMware Infrastructure with a typical Windows guest server taking fewer than 60 seconds to complete the startup process.
One application that's fairly common for our consulting clients is to run Exchange 2007, a 32 bit Windows Server 2003 File Server, and 32-bit terminal server at a branch office. As you know, Exchange 2007 requires the 64-bit version of Windows 2003, so virtualization of these three servers allows the company to run all of its applications on a single server instead of purchasing three individual servers. Running the 32-bit version of Windows 2003 ensures the highest level of compatibility with applications since there are still some applications that won't run on the x64 platform. If you’re running into performance problems with the Exchange Management Console or Exchange Management Shell, make sure you have allocated adequate memory to the Exchange 2007 server. I suggest a minimum of 3GB of memory for a guest server running Exchange 2007 for a very small Exchange Server (10 or fewer users).
Using this solution does reduce your fault tolerance, because a problem with the host will cause all the guests to go down. Therefore, I suggest purchasing a 24X7 4-hour or less response time hardware support contract for any host running ESX Server. Purchasing a server with redundant power supplies and cooling fans is also a good idea.
One big difference with ESX is that you boot to an ESX kernel instead of Windows 2003. When the ESX server is booted, you open a Web browser and enter the IP address of the ESX server. From there you can either use the Web interface to manage your ESX guests, or download and install the VMware Virtual Infrastructure Client (VIC). Although you can perform most functions using the Web interface, I suggest using the VIC because it runs faster and allows you to perform all the ESX management functions. If you already know Linux (especially Red Hat variant), you’ll have a jump start on the ESX, because a lot of the navigation and commands are similar to Red Hat. If you’re not up to speed on Linux, don’t panic. You can still get around, but it may take you a bit longer to perform basic administrative tasks. Although most of the management tasks can be performed with the VIC, there are still some tasks that you will need to perform at the command line, like using vmdktools –i command to clone existing disk images, and possibly writing a script for the backup of guest disk images. Two utilities you want to get immediately are Putty (http://www.pcworld.com/downloads/file/fid,62687-order,1-page,1-c,alldownloads/description.html ), which will let you securely connect with Secure Shell (SSH) to the ESX console and WinSCP (http://winscp.net/eng/index.php ), which provides an explorer-like interface to copy files to/from a Windows machine and ESX host via SFTP or FTP. In the next article, I'll cover the installation of ESX and basic maintenance of this virtualization platform.
Tip
With the price on USB flash drive falling dramatically I purchased an 8GB key that allows me to carry around installation files, patches and utilities in one easily accessible location. This saves a lot of time during any new installation or upgrade, by eliminating the download time for essential files or patches. The only drawback is these drives tend to be a little larger than a standard USB flash drive and are sometimes difficult to insert in a USB slot, especially on older computers. Consider purchasing a USB extension cable for use when space is limited.
