?
Solved

Vmware CPU - how to work out Vcpu per core

Posted on 2012-09-21
7
Medium Priority
?
2,497 Views
Last Modified: 2012-10-14
I am so confused as to how many machines you can have per core on a esxi host.

For example: I was under the impression that if you have a 4 core Xeon processor with hyperthreading that you would be able to handle 8 VM's (because you have 8 logicial CPU's)? before you would create a round house effect where the vm's would 'que' for CPU access.

The above example i found in a blog - would that be incorrect?

But reading this:
http://www.experts-exchange.com/Networking/Network_Management/Auditing_Software/Q_27075853.html

Hancocka is running 48 machines on 4 cores?

Is there something that i am missing?

All we are looking to run on our host is VDI's that are assigned 1vCPU.
0
Comment
Question by:Kenzii
7 Comments
 
LVL 4

Expert Comment

by:filaa
ID: 38420999
Hello Kenzii,

You can have more vCPUs than physical CPU but that is not best practice in production environment.


More about that on link below
http://www.vmware.com/pdf/Perf_Best_Practices_vSphere5.0.pdf

Best Regards,
Fila
0
 
LVL 15

Accepted Solution

by:
Raj-GT earned 2000 total points
ID: 38421005
VMware and all type 1 hypervisors use scheduling to handle access to physical resources so yes, you can allocate a single CPU core to multiple vCPUs.

you may need to take some care for VDI though, read the blog below for some more information on scheduling for VDI.

http://blog.danbrinkmann.com/2012/06/06/the-cpu-scheduler-and-vdi/
0
 
LVL 24

Expert Comment

by:Nagendra Pratap Singh
ID: 38421139
VMware and others all use the round house thing.

Most VMs are idle at least for some time and at that moment don't participate in queues etc.

You can have 20 VMs running on a single Xeon box.
0
Threat Trends for MSPs to Watch

See the findings.
Despite its humble beginnings, phishing has come a long way since those first crudely constructed emails. Today, phishing sites can appear and disappear in the length of a coffee break, and it takes more than a little know-how to keep your clients secure.

 
LVL 124
ID: 38421182
not really, because you can have as a rule of thumb 5-6 VMs per physical core.

and this is because of the Hypervisor clever CPU scheduler, which switches CPU cycles/time between VMs.

and as you've quote me, we also run between 80-100 VDI Workstations on a Dell R810 128GB 24 Cores.

This is less than are normal 5-6 VMs, because these are usually servers, that are idle for most of the time, compared to Desktops in use by Students every timetabled hour, which are busier.
0
 

Author Comment

by:Kenzii
ID: 38421260
Ok,
So this is how we have things setup at the moment:

all servers reside on a seperate box. So idleing will generally occur on this.

Our main box that we are looking to use for VDI boxes. 16GB RAM Xeon E31230 3.20Ghz

4 VDI's on this box with 2GB RAM each and 1vCPU.

Looking into this it appears as soon as we play a video through the VDI that will use flash redirection it hammers all VDI's on the server. But CPU % sits around 25%.

We use quest vWorkspace which provisions the VDI's and then provides the connection.

Our internet line is 100MB down. 10mbs UP. which with 4 machines connecting to the internet does not seem alot.

But sounds like this is not going to a CPU problem after all.
0
 
LVL 124
ID: 38421291
Flash does cause High CPU utilisation.

A Dual Processor Server is probably better here, and more RAM in the Host.

Because the scheduler can allocate cores across multiple physical processors, rather than just a single.
0
 
LVL 4

Expert Comment

by:filaa
ID: 38421348
Flash player in VDI works slow.

You can find similar questions on the internet.
http://communities.vmware.com/message/1147231

Look at Flash acceleration :
http://www.rapporttechnologies.com/products/software/tcx/index.asp


And VMware View Flash Optimizer plugin
http://myvirtualcloud.net/?p=2479

Hope this will help.

Br,
Fila
0

Featured Post

Get quick recovery of individual SharePoint items

Free tool – Veeam Explorer for Microsoft SharePoint, enables fast, easy restores of SharePoint sites, documents, libraries and lists — all with no agents to manage and no additional licenses to buy.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In this article, I will show you HOW TO: Perform a Physical to Virtual (P2V) Conversion the easy way from a computer backup (image).
Giving access to ESXi shell console is always an issue for IT departments to other Teams, or Projects. We need to find a way so that teams can use ESXTOP for their POCs, or tests without giving them the access to ESXi host shell console with a root …
Teach the user how to edit .vmx files to add advanced configuration options Open vSphere Web Client: Edit Settings for a VM: Choose VM Options -> Advanced: Add Configuration Parameters:
Teach the user how to use create log bundles for vCenter Server or ESXi hosts Open vSphere Web Client: Generate vCenter Server and ESXi host log bundle:  Open vCenter Server Appliance Web Management interface and generate log bundle: Open vCenter Se…
Suggested Courses

850 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question