Beefing up a VM - Hyper-V

[saintoctopus]

Ok, I'm trying to get my head around this and Google is no help whatsoever! Some IT people have forgotten how to speak English, I swear! I wonder if someone out there in EduGeekLand can help me...

 

We currently have a physical server for our MIS (which shall remain nameless) but we also run a hyper-v server farm; four hosts, each with 2x quad core processors and 64GB of memory. The hypervisor is hyper-v...

 

The MIS is performing woefully bad, and we need to give it more...well, more! (It has been suggested that we should have 16 cores and 16GB of memory... what am I running here? A weather centre?)

 

Now, the physical server has 1 quad core processor, which obviously runs as 8 logical processors. I wanted to run a VM with more power than the physical server. I can give it a boat load of memory, but I can only assign 4 virtual processors to it. The solution has been suggested, therefore, that we throw more power at the physical server - but I am unconvinced that this is the best thing to do... feels like we're taking a step backwards.

 

Are virtual processors the same as physical or logical cores, or does Hyper-V allocate it differently? Is a VM with 4 virtual cores likely to be more powerful if it is running on one of my uber-hosts, or not? Is it possible to allocate more than 4 cores or is that unecessary?

 

You understand my confusion. I'm a simple being - please be gentle with me!

 

Thanks in advance...

[Psymon]

HyperV 2008R2 only support allocating 4 cores to a VM - this answes one question.

 

Now, the physical server has 1 quad core processor, which obviously runs as 8 logical processors. I wanted to run a VM with more power than the physical server. I can give it a boat load of memory, but I can only assign 4 virtual processors to it. The solution has been suggested, therefore, that we throw more power at the physical server - but I am unconvinced that this is the best thing to do... feels like we're taking a step backwards.

 

This won't make a difference as you are limited by CPU - what's the memory utilization on thie MIS host? Are you using dynamic memory?

 

You cannot over-allocate CPUs anyway - it still only uses the CPUs from the host server (it cannot use other hosts CPU power as well - even if clustered etc...).

 

 

Alternatively you look at upgrading your hosts -

 

Server 2008R2 - 4 virtual processors, and up to 64 GB of memory on a virtual machine

Server 2012 - 64 virtual processors, and up to 1 TB of memory on a virtual machine

 

Useful 2008R2 vs 2012 PDF - http://download.microsoft.com/download/2/C/A/2CA38362-37ED-4112-86A8-FDF14D5D4C9B/WS%202012%20Feature%20Comparison_Hyper-V.pdf

 

Simon

Edited February 19, 2013 by Psymon
Added useful PDF link.

[strawberry]

upgrade to server 2012, it allows more cores per vm.

[pantscat]

Have you checked out where the resource constraint is on the physical server?

 

Surely you need to know why it's performing badly before you do something about it?

[3s-gtech]

Looking into doing this myself very soon, but using ESXi instead. I'm planning to have the MIS VM as the only VM on the host though - just virtualising so I can P2V it and use some of the other benefits of ESXi. I'll be doubling the number of cores and RAM, plus massively increasing the number of disk spindles available. There are minor overheads involved, but you should still see a performance jump as long as you can allocate for it.

[saintoctopus]

Thanks for your thoughts. I will be looking into upgrading to 2012, but not just yet!

 

In the meantime, I adjusted the associated XML file and gave the VM 8 virtual cores. Seems to be working brilliantly!

 

Tara a bit!

[fiza]

In the meantime, I adjusted the associated XML file and gave the VM 8 virtual cores. Seems to be working brilliantly!

 

Tara a bit!

 

I though 2008 R2 was limited to 4 vCPUs. How did you allocate 8?

[saintoctopus]

I though 2008 R2 was limited to 4 vCPUs. How did you allocate 8?

 

Just like this:

[fiza]

Just like this:

 

Has anyone else attempted this?

[saintoctopus]

 

It seems to work!