Specifications

Administration Guide
364 VMware, Inc.
with!testing!to!confirm!that!memory!sizes!computed!according!to!these!guidelines!
achieve!the!results!you!want.
ESX!Server!uses!a!small!amount!of!memory!for!its!virtualization!layer,!additional!
memory!for!the!service!console,!and!all!remaining!memory!for!running!virtual!
machines.!The!following!sections!explain!each!of!these!uses!
and!provide!a!quantitative!
sizing!example.
Server Memory
ESX!Server!2.5!uses!approximately!24MB!of!system!memory!for!its!virtualization!layer.!
This!memory!is!allocated!when!the!ESX!Server!is!loaded!and!is!not!configurable.
Service Console Memory
The!recommended!amount!of!memory!to!configure!for!the!service!console!varies!
between!192MB!and!512MB,!depending!on!the!number!of!virtual!machines!you!plan!to!
run!concurrently!on!the!server:
! 192MB!for!<=!8!virtual!cpus
! 272MB!for!<=!16!virtual!cpus
! 384MB!for!<=!32!virtual!cpus
! 512MB!for!>!32!virtual!cpus
The!maximum!amount!of!memory!that!can!be!reserved!is!800MB.
Virtual Machine Memory Pool
The!remaining!pool!of!system!memory!is!used!for!running!virtual!machines.!ESX!
Server!manages!the!allocation!of!this!memory!to!virtual!machines!automatically!based!
on!administrative!parameters!and!system!load.!ESX!Server!also!attempts!to!keep!some!
memory!free!at!all!times!in!order!to!handle!dynamic!allocation!requests!efficiently.
!ESX!
Server!sets!this!level!at!approximately!6!percent!of!the!memory!available!for!running!
virtual!machines.
Virtual Machine Memory
Each!virtual!machine!consumes!memory!based!on!its!configured!size,!plus!additional!
overhead!memory!for!virtualization.
N
OTE The!amount!of!memory!required!must!also!take!in!to!account!the!amount!of!memory!
required!by!system!management!agents!or!backup!agents!that!will!be!running!in!the!
service!console.