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big_vern
Enthusiast
Enthusiast

AMD-V and 64 BIT guests (windows 2008) - enable ?

Hi,

( don't worry the questions not too long,, just included all the info I could think you may need)

We have a 2 separate 5 server clusters set up, running esx 3.5 U3 (I know windows 2008 64 bit isn't officaiy supported on this version)

cluster 1 = 5 x HP BL685c G1

CPU: cat /proc/cpuinfo

processor : 0

vendor_id : AuthenticAMD

cpu family : 15

model : 65

model name : Dual-Core AMD Opteron(tm) Processor 8216

stepping : 2

cpu MHz : 2411.136

cache size : 1024 KB

fdiv_bug : no

hlt_bug : no

f00f_bug : no

coma_bug : no

fpu : yes

fpu_exception : yes

cpuid level : 1

wp : yes

flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx mmxext lm 3dnowext 3dnow

bogomips : 4810.34

cluster 2 = 5 x HP BL465c G5

CPU: cat /proc/cpuinfo

processor : 0

vendor_id : AuthenticAMD

cpu family : 16

model : 2

model name : Quad-Core AMD Opteron(tm) Processor 2356

stepping : 3

cpu MHz : 2300.134

cache size : 512 KB

fdiv_bug : no

hlt_bug : no

f00f_bug : no

coma_bug : no

fpu : yes

fpu_exception : yes

cpuid level : 5

wp : yes

flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall mmxext lm 3dnowext 3dnow

bogomips : 4587.52

We have been having performance issues with with windows 2008 r2 guests (64 bit) whereby they fail to reboot - just get a black console even thought the VM shows as being powered on or they take 30 minutes or more to boot up. We have over 150 windows 2003 VMs running on the same boxes without issue .

Triubleshooting led to the following message when using the vi client connected directly to one of the esx boxes witht he problem VM:

"this cpu supports the amd-v hardware virtualization feature, but amd-v is disabled. Check your bios/firmware settingsfor potential performace improvement"

Done some googling but am now more confused

1) Should I be enabling this (It doesn't suggest I have to do it), is there any official recommednation from VMware?

2) If I do enable it do I have to be concerned about the performance impact on the existing windows 2003 VMs ?

3) Do you think this will solve the problem?

cheers

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8 Replies
AndreTheGiant
Immortal
Immortal

The AMD-V instruction are required to run x64 OS.

So enable them.

And upgrade all your BIOS, and if possible also your ESX 3.5 (to at least U5).

Andre

Andrew | http://about.me/amauro | http://vinfrastructure.it/ | @Andrea_Mauro
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big_vern
Enthusiast
Enthusiast

HI Andre,

We are soon upgrading to U5.

The windows 2008 have been running ok up to now without AMD-V, which is why I was questioning how it was doing so. Is there nay offical VMware statement explicitily stating AMD-V must be enabled to run 64-bit OS?

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mittim12
Immortal
Immortal

AMD-V also enables the hardware virtulization which will help performance in some cases. To enable it you have to go into the bio, advanced, options, processor options, and enable.






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AndreTheGiant
Immortal
Immortal

Is there nay offical VMware statement explicitily stating AMD-V must be enabled to run 64-bit OS?

Although is more explict on Intel, see this KB:

http://kb.vmware.com/kb/1003944

Andre

Andrew | http://about.me/amauro | http://vinfrastructure.it/ | @Andrea_Mauro
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admin
Immortal
Immortal

AMD-V is not required to run 64-bit guests. See KB 1003945.

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big_vern
Enthusiast
Enthusiast

Ok - thanks chaps - I'll award points at the end,,

So does / can turning this on have any effect on (good or bad) on exisiting windows 2003VMs ?

We have a rigourous RFC process which I know will ask this question.

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mittim12
Immortal
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I think it would be good for VM's that can make use of the hardware virtulization abilities of the server.






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admin
Immortal
Immortal

So does / can turning this on have any effect on (good or bad) on exisiting windows 2003VMs ?

It should have no effect on 32-bit Windows 2003 VMs under ESX 3.5. For ESX 3.5, the only 32-bit guests that default to using AMD-V, if available, are OpenServer, UnixWare, and OS/2.

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