Quick Hyper-v question

[Jobos]

Not sure how virtual processors work with Hyper-v so need a bit of advice please

 

Server 2012 with 2 x E5-2620 cpu's.

 

Task manager shows 12 cores and 24 logical processors. When setting up the virtual machines how many virtual processors have I got to play with? Is it 12 or 24? I understand I need to keep some cpu's back for the host.

 

Thanks.

[VeryPC_Ed]

Hyper-V performance tuning – Part 1: Virtual processors - 4sysops

 

Good article on Hyper-V Virtual Processors

[Jobos]

Thanks. So going by that I can use 11 cores in the VM's and 1 for the host.

[Colditzz]

Thanks. So going by that I can use 11 cores in the VM's and 1 for the host.

 

Count the 11 cores and then multiply by four, this gives you the 'comfortable' ratio of logical to physical processor count. To discover current ratio, run the PowerShell command in this link - Using PowerShell to find the virtual processor to logical processor ratio of Hyper-V - Ben Armstrong - Site Home - MSDN Blogs - you will find the same page linked from VeryPC_Ed's reply above. You can run to a multiple of 8 (under 2008 R2) but that is the maximum you should do.

 

Hth

Edited June 23, 2013 by Colditzz

[LCPSWolf]

Colditzz,

 

Beautiful post and recommendations. Thanks! I'm a new 2012 HyperV admin and the rule of thumb is good - though I feel like I'll max out my available RAM long before maxing out my processor count!

[Jobos]

Update:

A very good article on assigning CPU resources has been published Maximizing Your Virtual Machine Density in Hyper-V (Part 4) which make a good read.