Specifications

VMware, Inc. 331
Chapter 12 VMware ESX Server Resource Management
CPU Resource Management
VMware!ESX!Server!provides!dynamic!control!over!both!the!execution!rate!and!the!
processor!assignment!of!each!scheduled!virtual!machine.!The!ESX!Server!scheduler!
performs!automatic!load!balancing!on!multiprocessor!systems.
You!can!manage!the!CPU!resources!on!a!server!from!the!VMware!Management!
Interface,!from!the!procfs!interface!on!the!
service!console,!and!from!the!VMware!
Scripting!API.
For!each!virtual!machine,!you!can!define!a!minimum!and!maximum!amount!of!CPU!
that!a!virtual!machine!can!use,!guaranteeing!a!percentage!of!the!CPU!resource.!You!also!
allocate!CPU!shares!to!specify!the!relative!importance!of!virtual!machines.
If!you!purchased!the
!VMware!Virtual!SMP!for!ESX!Server!product!and!your!guest!
operating!system!is!SMP‐capable,!you!can!control!whether!the!virtual!machine!runs!on!
one!or!two!CPUs!and!restrict!a!virtual!machine!to!run!only!on!certain!physical!CPUs.!
For!more!information!on!the!VMware!Virtual!SMP!for!ESX!
Server!product,!contact!
VMware,!Inc.!or!your!authorized!sales!representative.
For!information!on!CPU!management!by!VMware!ESX!Server,!see!the!cpu(8)!man!
page.
Allocating CPU Resources
Three!parameters!control!the!allocation!of!CPU!resources!to!each!virtual!machine:
! Minimum!rate!(min)
The!minimum!CPU!percentage!represents!an!absolute!fixed!lower!limit!of!a!single!
physical!CPU’s!processing!power.!The!virtual!machine!will!always!be!able!to!use!
this!minimum!percentage!of!a!CPU’s!resources,!regardless!of!what!else!is!
happening!on!the!server.!The!system!uses!an!admission!control!
policy!to!enforce!
this!guarantee.!You!cannot!power!on!a!new!virtual!machine!if!it!cannot!reserve!its!
minimum!CPU!percentage.
! Maximum!rate!(max)
The!maximum!CPU!percentage!represents!an!absolute!fixed!upper!limit!on!the!
consumption!of!a!single!physical!CPU’s!processing!power.!The!virtual!machine!
will!never!consume!more!than!this!maximum!percentage!of!a!CPU’s!resources,!
even!if!idle!time!is!on!the!system.
! Shares!allocation
CPU!shares!entitle!a!virtual!machine!to!a!relative!fraction!of!CPU!resources.!For!
example,!a!virtual!machine!that!has!twice!as!many!shares!as!another!is!generally!