6.0.1

Table Of Contents
Administering Memory Resources 6
Using the vSphere Web Client you can view information about and make changes to memory allocation
settings. To administer your memory resources effectively, you must also be familiar with memory
overhead, idle memory tax, and how ESXi hosts reclaim memory.
When administering memory resources, you can specify memory allocation. If you do not customize
memory allocation, the ESXi host uses defaults that work well in most situations.
You can specify memory allocation in several ways.
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Use the attributes and special features available through the vSphere Web Client. The
vSphere Web Client allows you to connect to the ESXi host or vCenter Server system.
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Use advanced settings.
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Use the vSphere SDK for scripted memory allocation.
This chapter includes the following topics:
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“Understanding Memory Overhead,” on page 35
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“How ESXi Hosts Allocate Memory,” on page 36
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“Memory Reclamation,” on page 37
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“Using Swap Files,” on page 38
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“Sharing Memory Across Virtual Machines,” on page 42
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“Memory Compression,” on page 43
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“Measuring and Differentiating Types of Memory Usage,” on page 44
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“Memory Reliability,” on page 45
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“About System Swap,” on page 45
Understanding Memory Overhead
Virtualization of memory resources has some associated overhead.
ESXi virtual machines can incur two kinds of memory overhead.
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The additional time to access memory within a virtual machine.
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The extra space needed by the ESXi host for its own code and data structures, beyond the memory
allocated to each virtual machine.
VMware, Inc.
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