Intel & AMD No of VM's per core

[Rajeev_S]

Hi,

In esx4.1 config max, it states i can run 25 vCPU per core.

Does this value increase when using Hyperthreading in Intel CPU's?

We are planning for a Virtual desktop setup, all the VD's will have 1 vCPU. For this setup if i go with Intel HT does it increase the number to 50?

Also does AMD has any kind of SMT technology?

Any inputs would be really helpful!

Thanks

Rajeev

[dquintana]

Hello Rajeev S,

In VDI, over Intel, i estimate no more than 10 VMs with 1 vcpu per core, with this configuration i have good performance and price per server.

My 2 cents.

Diego Quintana

[idle-jam]

we run about 8-10 VM per cores. i use this calculator and i think you will find it useful: http://myvirtualcloud.net/?page_id=1076

[Rajeev_S]

Thanks  . I'm happy to run 12 or less vCPU's per core.

My confusion is, by enabling HT does it makes difference in number of vCPUs that can scheduled on a core?

Because with HT enabled on a Quad core Dual Processor I see 16 pCPU on ESXTOP. Does this mean i can schedule more VM's on a core (i.e) double.

Hope i'm clear !!

[mittim12]

The number listed in the maximum configuration guide is the maximum that VMware supports.  So in reality hypthreading may allow you to get more but 25 is still what VMware supports.

[Rajeev_S]

correct me if i'm wrong.

Does it mean i can run more Virtual Desktops with Intel Processor - HT enabled than in AMD?

[mittim12]

I would say there is a good chance that you will be able to run more but nothing is for certain.    To be honest my bottleneck in VDI has never been processor but instead memory.   If you use a 8 core server and get 25 per core your looking at a ton of memory.

[Rajeev_S]

Why i'm concerned is, AMD provides a cheaper price deal than Intel.

I'll save some $$$$ on that.

So, do you suggest i can go for AMD. As there wont be much performance benefit for me with HT for VD.

[mittim12]

I don't know if I can recommend either one.  You have to choose what works best for your budget and your environment.   We have currently standardized on the Intel processors for our environment. 

[chriswahl]

Another consideration, beyond raw compute, is the consolidation risk of scaling up.

Questions to ask yourself include:

1. How many VMs are you willing to lose in the event of a host failure?
2. How long will HA take to handle restarting those VMs?
3. Will the SAN be able to survive a boot storm of that magnitude?

[golddiggie]

Depending on how the virtual desktops are configured, you should be able to get up to 25 View desktops per socket on the host server. As already mentioned, though, RAM in the host box will be a bigger issue for you. Rule of thumb is to consider whatever each VM is set to use for RAM, as fully allocated from that host. So if you have VM's with 2GB of RAM allocated, you'll want at least View Desktops x 2GB of RAM in the host (plus for overhead)...

We're working on a View PoC and pilot right now. The hosts we're ordering for the first round of deployments won't have an issue with CPU resources (dual socket, 6 cores per socket Xeon's) but would have run into RAM issues. The original server spec's only had 96GB of RAM in each box. For some reason the person that originally planned the configuration was only looking at CPU resources for how many desktops per host server. We have been informed (more recently) about how to properly plan the host servers for View deployments. So, our host servers will have 192GB of RAM inside them. I'm projecting being able to run about 80 virtual desktops per host that way.This should work for both XP (what we're running now) and for when we go to Windows 7 (later this year is the plan). 

So, as long as you have the RAM, and storage, CPU resources shouldn't be a concern... Of course, I would opt for Xeon's over AMD processors any day of the week, for any task.

[Rajeev_S]

Thanks a lot for the inputs everyone.

We've computed the RAM, disk IOpS and other details and have sized as per our need. I beleive we are comforatble in that.

Would need a final comment on the below point,

- by using Intel Processors with HT, will i be able to run more VD's per core compared to AMD processors? 

Appreciate your inputs!!

[AndreTheGiant · Accepted solution]

- by using Intel Processors with HT, will i be able to run more VD's per core compared to AMD processors? 

No... you can only schedule them more efficiently.

HT cannot double the number of cores, in fact, if you have two vCPUs on one HT core (so it is a 2 logical processors) each VM will have 50% of the physical core power.

Andre

[Rajeev_S]

Thanks a lot Andre. That answers my question.

Appreciate everyone's ideas