jimbo789
Contributor
Contributor

Fault Tolerance and vCPUs

Is it true if I turn on Fault Tolerance that I am limited to 1 vCPU per VM? if this is true than how in tarnation does one setup FT on the modern processors which have multiple cores?

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9 Replies
mcowger
Immortal
Immortal

jimbo789 wrote:

Is it true if I turn on Fault Tolerance that I am limited to 1 vCPU per VM?

True

if this is true than how in tarnation does one setup FT on the modern processors which have multiple cores?

One doesn't.  In the current incarnation.  This limitation will likely be changed in future versions.

--Matt VCDX #52 blog.cowger.us
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depping
Leadership
Leadership

The virtual machines are limited to 1 vCPU. The physical machine can have multiple CPUs with multiple cores. At VMworld vSMP FT was demonstrated by the way. Unfortunately I can't comment on when this will be released.

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sergeadam
Enthusiast
Enthusiast

Does 1 vCPU imply single core, or can a multi core vCPU be configured?

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vmroyale
Immortal
Immortal

Hello.

1 vCPU = 1 single core. Multicore isn't possible currently.

Good Luck!

Brian Atkinson | vExpert | VMTN Moderator | Author of "VCP5-DCV VMware Certified Professional-Data Center Virtualization on vSphere 5.5 Study Guide: VCP-550" | @vmroyale | http://vmroyale.com
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depping
Leadership
Leadership

1vCPU / 1 Core is only thing possible right now!

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rupeshdnair
Enthusiast
Enthusiast

Duncan,

I am just making this doubly sure. Imagine I have 4 cores on my physical processor. Can I create a VM with 1 vCPU that uses all the 4 cores on the physical processor and enable FT on that VM?

Rupesh

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iw123
Commander
Commander

I believe it is 1 vcpu = 1 core. Specifying more virtual cores within the VM equates to using more vCpus. E.g. a VM with 1 vcpu/2 v cores is equal to a VM with 2 vCPU - therefore its not possible to use FT with this configuration. 

*Please, don't forget the awarding points for "helpful" and/or "correct" answers
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rickardnobel
Champion
Champion

rupeshdnair wrote:

Imagine I have 4 cores on my physical processor. Can I create a VM with 1 vCPU that uses all the 4 cores on the physical processor and enable FT on that VM?

Your VM with 1 vCPU could run at any of your physical cores, but at a certain moment in time it will only execute on one of them. The VMkernel will schedule all your VMs vCPUs on the most suitable cores depending on the exact need at the moment.

My VMware blog: www.rickardnobel.se
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rupeshdnair
Enthusiast
Enthusiast

Thanks for the clarifications guys.

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