Specifications

VMware, Inc. 361
Chapter 12 VMware ESX Server Resource Management
other!nodes.!ESX!Server!rebalances!the!nodes!by!changing!a!virtual!machine’s!“home”!
NUMA!node!from!the!overutilized!node!to!an!underutilized!node.!
When!the!NUMA!nodes!are!balanced,!ESX!Server!again!attempts!to!maximize!use!of!
“local!memory.”!For!more!information,!refer!to!the!numa!man!page.
You!can!also!
set!affinity!manually!as!described!in!the!next!section.!If!you!do,!ESX!Server!
won’ t!automatically!rebalance!the!nodes,!and!you!must!balance!the!NUMA!nodes!to!
avoid!overloading!any!single!node.
Manual NUMA Optimizations
If!you!have!applications!that!use!a!lot!of!memory!or!have!a!small!number!of!virtual!
machines,!you!might!want!to!optimize!performance!by!setting!your!NUMA!
optimizations!manually.!For!most!users,!ESX!Server’s!automatic!NUMA!optimizations,!
should!provide!you!with!good!performance.
You!can!set!two!NUMA!options!manually:
! CPU!affinity!–!See!“As s o c i a t i n g !Virtual!Machines!to!a!Single!NUMA!Node,”!next.
! Memory!affinity!–!See!“A s s o c i a t i n g !Future!Virtual!Machine!Memory!Allocations!
with!a!NUMA!Node”!on!page 362.
Typically,!to!bind!a!virtual!machine!to!a!NUMA!node,!set!the!virtual!machine’s!CPU!
affinity!to!use!only!the!CPUs!on!the!specified!node!and!set!the!NUMA!memory!affinity!
to!the!same!node.
Associating Virtual Machines to a Single NUMA Node
You!can!improve!the!performance!of!the!applications!on!a!virtual!machine!by!
associating!it!to!the!CPU!numbers!on!a!single!NUMA!node!(manual!CPU!affinity).!
(“NUMA!Configuration!Information”!on!page 358.)
! VMware!Management!Interface!–!Associate!a!virtual!machine!to!a!single!NUMA!
node.!Click!Edit!in!the!Scheduling!Affinity!section!of!the!CPU!page!for!the!virtual!
machine.!Click!the!appropriate!choices!next!to!Run!on!Processor(s)!and!Do!not!
Run!on!Processor(s).!Click!OK.
See!“Managing!CPU!Resources!from!
the!Management!Interface”!on!page 336.
! Virtual!machine!configuration!file!–!Add!the!following:
sched.cpu.affinity = <set>
NOTE If!you!set!these!optimizations!manually,!ESX!Server!does!not!automatically!“rebalance”!
the!nodes!if!one!node!becomes!overloaded.!You!must!balance!the!NUMA!nodes!to!
avoid!overloading!any!single!NUMA!node.