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Table Of Contents
VMware, Inc. 275
Chapter 12 Performance Tuning for VMware Server
Increasing NIC Interrupt Coalescing
InterruptcoalescingisaconfigurablefeatureinhighperformanceNICs.Interrupt
coalescingprovidesnotificationofthereceptionofagroupofnetworkframestothe
operatingsystemkernelthroughhardwareinterrupts.Increasinginterruptcoalescing
onhostNICscanimproveperformanceforworkloadsinvolvingheavynetworktraffic
totheguestsystem.
Calculating Memory Requirements to Allow for Virtual Machine
Overhead
Virtualmachinesrequirerelativelylargeamountsofmemorytoperformwell.Each
virtualmachinecanusememoryuptoitsallocationlimit,plussomeoverhead.The
amountofoverheadneededdependsonthesizeofthevirtualdisks,theamountof
memoryallocatedtothevirtualmachine,andguestsystembehavior.
Table 121liststheadditionalamountofmemoryneededforoverhead,basedonthe
amountofmemoryallocatedtothevirtualmachine.
Donotallowtotalmemoryallocatedforallrunningvirtualmachinesplustheoverhead
forVMwareServerprocessestoexceedtheamountofphysicalmemoryonthehost.
Also
keepsomememoryavailableforotherapplicationsonthehost.
Configuring Host-Wide Virtual Machine Memory Usage
Inadditiontoconfiguringthememorycapacityforeachvirtualmachine(see
AllocatingMemorytoaVirtualMachine”onpage 277),youcanspecifythefollowing
hostwideVMwareServermemorysettings:
Howmuchofthehostsystem’smemorycanbeusedforallrunningvirtual
machines
Theextenttowhichthehostsystem’smemorymanagercanswapvirtualmachines
outofphysicalRAM
Thesesettingsaffectbothvirtualmachineandoverallsystemperformance.
Table 12-1. Virtual Machine Allocated Memory and Additional Memory Overhead
Virtual Machine Memory Allocated Additional Memory Overhead Needed
Upto512MB Upto54MB
Upto1000MB Upto62MB
Upto2000MB Upto79MB
Upto3600MB Upto105MB