IT publications tend to kick around the term systems management indiscriminately. Systems management, especially systems management on VMware, can mean a lot of different things. But in this chapter of our ESX Server runbook, we'll discuss three central components: capacity planning, systems monitoring and availability. Follow the links in this guide for more information.
VMware ESX has essentially become the standard enterprise virtualization platform. Nonetheless, system administrators need to consider the best way to manage virtual infrastructures. Although some best practices can be carried over from the physical world, there are some special considerations when it comes to managing VMware ESX Server.
Capacity planning with VMware
Server consolidation has historically been a major virtualization driver. But saving space and optimizing usage via virtualization brings forth new questions about system requirements, capacity and workload allocation. It is important to understand how virtual servers change physical server requirements to get the most from your VMware implementation.
In order to help system administrators and data center staff alleviate capacity planning issues that virtualization rears, VMware offers Capacity Planner for ESX. This tool has some system monitoring capabilities that enables admins to assess and evaluate current capacity and plan for future growth.
Systems monitoring
VMware administrators have several tools at their disposal that can be leveraged to gather and export information about the ESX system software and the underlying physical server hardware. Free third-party tools, such as vmkusage and vmktree, gather and display system data.
For whole-system, agent-based monitoring, system administrators may find Hyperic Inc.'s offerings beneficial. Hyperic is especially useful because it can monitor virtual and physical systems. When used with VMware VirtualCenter, admins can get a better picture of performance in their environments.
Although there are many utilities outside of VMware for systems monitoring, ESX has useful tools built into its console. The esxcfg-info command, for example, provides information about the ESX host, including an inventory and details of the virtual machine on the host. For information regarding ESX resource usage, system admins can also refer to the esxtop command.
System redundancy and availability
When system administrators have appropriately determined their physical and virtual infrastructure capacity and have assessed and evaluated system performance, they may turn their attention to methods and tools for ensuring availability. There are many ways to accomplish varying levels of availability among your virtual servers, all of which depends on whether you need HA, hardware redundancy or other levels of availability.
VMotion is arguably VMware's major contribution to the virtualization space since its advanced compatibility with x86 servers. Understanding the ins and outs of using VMotion has its advantages. For instance, VMotion must be configured properly in order to avoid downtime.
VMotion comes with a price, but it is possible to obtain VMware ESX redundancy without VMotion. It requires some setting up the file server virtual machine and a scripted synchronization of the source virtual machine to another ESX server.
