Sharing resources

[redan83]

Hello,

I have the following hardware:

• PowerEdge R510

• Intel Xeon E5630 Processor (2.53GHz, 4C, 12M Cache, 5.86 GT/s QPI, 80W TDP, Turbo, HT), 1066MHz Max Memory

• 8GB Memory for 1CPU (4x2GB Dual Rank RDIMMs) 1066MHz

• 4x HD Hot Plug 300Go SAS 6Gbit/s 15000tr/min 3,5

I would like to install using VMware ESXi 4.1 the following servers :

1) Windows 2008 R2 dedicated to File System and Active Directory

2) Windows 2008 R2 dedicated to Symantec Backup Exec 2010

3) Windows 2008 R2 dedicated to Avaya VOIP Server

As I am no expert to ESXi, how do you recommend I share my resources (processors, memory, harddrive memory) ?

Thanks in advance.

Regards,

[FranckRookie]

Hi Redan,

Welcome to the forums.

Except if you have any special requirement for one of the three servers, I would suggest starting by sharing processor and memory resources equally between your virtual machines. Why not giving about 2GB of memory and one virtual CPU each? Then, in case it's not enough for one machine, give it more until your physical machine gets saturated. Create virtual disks according to the needs of each server.

Regarding your Avaya VOIP Server, maybe you should dedicate a physical network card to have all necessary bandwidth.

Good luck.

Regards

Franck

[ezzeldin72]

the famous answer "It depends":) since you did not run capacity planning tool to know exactly how much resources each VM need (and also know if it candidate for virtualization or not)

the good news you can start with any configuration then change it if need so you can create 3 VMs with 1vCPU/2G RAM and monitor the performance then apply any changes you may need.

[redan83]

Hello Franck,

Thank you for the quick reply.

If I give let's say 2 vcpu to the AD server. Is it a problem with esxi or w2008r2 if I reduce the vcpu down to 1 ?

What if I do that with hd or the memory ?

Thanks.

[redan83]

Hi,

Thanks.

Can I also reduce later (if I gave to much ...) ?

Best,

[ezzeldin72]

you can reduce it but while the VM offline. but the good thing that, you can increase it while the VM online

[redan83]

It will not be a problem for w2008r2 because I think read something like that on web .. So I can reduce anything will the vm is off ?

[ezzeldin72]

Yes you can(cpu/memory)

Best Regards,

Ezz

[golddiggie]

I would start with one vCPU in each VM, unless you have software that explicitly requires more processors. Even then, I'd still try with one vCPU first. It's easy to increase the vCPU count, where it typically requires more processes to reduce the count.

For the RAM, with only 8GB I see you running into issues pretty quickly... Even if you give each VM 2GB, they could start balooning or looking for more (2008 R2 wants 4GB by default/minimum)... While you can give it the lower number, keep a watch over how the VM's are performing and for balooning.

I'm running a 2008 R2 AD DC VM (not doing anything else) and it's using 1.5GB of RAM by itself (host memory, 2GB allocated)... This is in my home lab environment, so very little activity on the VM... I'm running eight VM's total here, using between 12GB and 13GB of the 16GB of RAM inside my host box... My Linux VM's (ftp, web server, and vMA) use the lowest amount of memory (each). The two SQL servers I'm running (2005, one 32 bit one 64 bit) use a higher percentage of the allocated memory (under the host memory stat)... While the guest memory stat is a low percentage (which is good) it's still something I keep an eye on...

I would suggest planning on getting more RAM for the server as soon as possible... Or before you think about adding more VM's to the box... Chances are, you'll be using a high percentage of what's inside right off the bat...

Which RAID controller did you go with inside that system?? If it doesn't have BBWC, then you could be looking at some rather poor performance from the drives...

VMware VCP4

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[redan83]

Hi.

Thanks.

I have by mistake allocated 2vcpu per server. Is it a problem to reduce the count (besides the long processes) ?

Or should i reinstall the vm from scratch ?

Thanks,

[ezzeldin72]

Just reduced it

[redan83]

Great and useful answers.

[golddiggie · Accepted solution]

Just make sure the HAL is correct when you reduce the processor count... After Server 2003 SP2 you didn't need to do anything special to change the HAL from uni to multi-processor. Other than the server will need to reboot to have the change take effect. I've not needed to do that on the 2008 releases yet... I would imagine that reducing the CPU's turning it from a multi- to uni-processor will require a reboot to have it take effect... Memory can be hot-add, and not require a reboot, but I'm pretty sure that changing the CPU will require bouncing the VM/server... It's still faster than if you had a physical box, but it will take a moment (or two)...

Before making any hardware changes (other than minor ones) I would take a snapshot on that VM... That way you can always roll back to before the change was made and be good again... Don't let the snapshot hang around though. Give it a reasonable amount of time (hours at most) and then delete the snapshot (via the snapshot manager)...

With the single CPU (even though it's quad core) I wouldn't recommend giving any VM more than two vCPU's... That is, until you've added another processor to the host... Good general rule of thumb is to not give any VM more than 50% of your host cores count... Such as (in my environment) I have dual quad core Xeon's powering my host (E5405's)... I wouldn't give any VM more than 4 vCPU's ever... Better off with either one or two vCPU's... Performance actually degrades on the VM's once you go over that 50% line (not just from me, there are plenty of people coming to the same discovery)... Keeping it to two vCPU's often will perform just as well, if not better, than four vCPU's (even if you have dual quad core processors in the host)...

VMware VCP4

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