6.5.1

Administering Memory Resources 6
Using the vSphere Web Client you can view information about and make changes to memory allocation
seings. To administer your memory resources eectively, 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.
n
Use the aributes 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.
n
Use advanced seings.
n
Use the vSphere SDK for scripted memory allocation.
This chapter includes the following topics:
n
“Understanding Memory Overhead,” on page 33
n
“How ESXi Hosts Allocate Memory,” on page 34
n
“Memory Reclamation,” on page 35
n
“Using Swap Files,” on page 36
n
“Sharing Memory Across Virtual Machines,” on page 40
n
“Memory Compression,” on page 41
n
“Measuring and Dierentiating Types of Memory Usage,” on page 42
n
“Memory Reliability,” on page 43
n
“About System Swap,” on page 43
Understanding Memory Overhead
Virtualization of memory resources has some associated overhead.
ESXi virtual machines can incur two kinds of memory overhead.
n
The additional time to access memory within a virtual machine.
n
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.
33