Dynamic logical partitioning involves:

￿Partitioning server resources

The ESX Server acts as the host operating system, provides dynamic logical partitions to hold other operating systems, and virtualizes most system resources, including processors, memory, network capacity, and disk controllers.

￿Isolating server resources

With ESX Server, each hosted operating system thinks it owns the entire computer, yet it sees only the resources that the administrator (through ESX Server) assigns to it. As shown in Figure 3-11 on page 99, ESX Server resides between the hardware and the various operating systems and applications. Partitions can be administered remotely, even down to the BIOS level, just as individual servers are.

Partitions

Windows 2000

Windows NT EE

Red Hat Advanced Server

SuSE Linux Enterprise

NetWare

Virtual layer

Physical layer

VMware ESX Server

Server hardware

Figure 3-11 ESX Server resides between the server hardware and server resources

￿Managing server resources

The ESX Server’s advanced resource management controls allow you to guarantee service levels. CPU capacity can be allotted on a time-share basis. Memory can be assigned dynamically based on partition workloads and defined minimums. If the allocated amount is insufficient in one partition, ESX Server can temporarily borrow memory from one partition and lend it to another, and then restore it to the original partition when needed. Network sharing is determined by token allocation or consumption based on the average or maximum bandwidth requirements for a partition.

Chapter 3. Planning 99

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IBM 440 manual VMware ESX Server