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Posted to user@vcl.apache.org by "Basilio, Norvin" <nb...@odu.edu> on 2013/02/12 15:35:44 UTC
Question on how people are configuring their VM computers
Hello,
I am curious on how others are configuring their VM computers. Right now I have configured groups of computers with ram configurations of 1GB, 2GB, 4GB, and 8GB. I've also grouped images the same way and mapped them to the corresponding computer groups. My problem with this method is that I have obviously limited the total numbers as it will not load 8GB vm computers with a 1GB image. I would like to know if I configure the the VM computers all as 8GB VM's will the vcl code stop any over provisioning the esxi hosts?
Norvin Basilio
Email: nbasilio@odu.edu<ma...@odu.edu>
Re: Question on how people are configuring their VM computers
Posted by Aaron Coburn <ac...@amherst.edu>.
The short answer is yes, the VCL will prevent over-provisioning of the VM hosts.
...
The long answer is when you configure the RAM on a certain computer, that value will be the maximum RAM given to the image when it starts up. The actual amount of RAM assigned to a VM is controlled by the setting on the image.
So, for example, if nodes 1-10 each have a RAM setting of 8GB, but all are running 4GB images then they will "consume" only 40 GB of the available RAM on the host.
You will also notice that each VM host has a total amount of RAM allocated to it, so, if your host has 80 GB of total RAM, then the VCL will only allow 10 8GB images or 20 4GB images -- any combination of images that fit into that total value.
That said, in my experience working with VMware, it is also possible to oversubscribe RAM. That is, if a given VM is configured to use 4GB of RAM, it most likely is only using a small portion of that. So your 10 4GB images may *actually* be using only 8GB of physical RAM. The difference between allocated RAM usage and actual RAM usage will depend entirely on the types of applications being used.
In our system, I oversubscribe the RAM on our host clusters by about 25% (not including the RAM used by VMware ~250MB/VM), and I have yet to see the actual RAM usage rise to a level that would even begin to concern me. In terms of where to set those values, I simply monitored the VM host performance data and incrementally increased the number of VMs to a level where I felt I was maximizing the CPU - RAM - I/O resource performance over the largest number of VMs.
I hope that helps.
Best regards,
Aaron
--
Aaron Coburn
Systems Administrator and Programmer
Academic Technology Services, Amherst College
acoburn@amherst.edu<ma...@amherst.edu>
On Feb 12, 2013, at 9:35 AM, "Basilio, Norvin" <nb...@odu.edu>>
wrote:
Hello,
I am curious on how others are configuring their VM computers. Right now I have configured groups of computers with ram configurations of 1GB, 2GB, 4GB, and 8GB. I've also grouped images the same way and mapped them to the corresponding computer groups. My problem with this method is that I have obviously limited the total numbers as it will not load 8GB vm computers with a 1GB image. I would like to know if I configure the the VM computers all as 8GB VM's will the vcl code stop any over provisioning the esxi hosts?
Norvin Basilio
Email: nbasilio@odu.edu<ma...@odu.edu>
RE: Question on how people are configuring their VM computers
Posted by "Basilio, Norvin" <nb...@odu.edu>.
Thanks all for the quick response. While I was testing some options on my vcl test environment I started to see the scenario's you all have described. That is what brought the original question up. You have provided me with the confirmation that I was looking for to move forward. Thanks
Norvin
Email: nbasilio@odu.edu
-----Original Message-----
From: Dmitri Chebotarov [mailto:dchebota@gmu.edu]
Sent: Tuesday, February 12, 2013 10:22 AM
To: user@vcl.apache.org
Subject: Re: Question on how people are configuring their VM computers
Hi Norvin
In our environment all VM computers configured with largest amount of resources (MEM, CPU) needed by an image.
I.e. if you have an image which needs 4 vCPU/8GB of memory then ALL VM computers would have4 vCPU and 8GB.
The VM computer configuration basically means 'up to' specified resources, it doesn't mean that all images will be loaded with max resources (4vCPU/8GB).
When you make a reservation/reload request for an image, it will be loaded on any VM computers which has adequate resources, but the image will be loaded with resources you specify for the image. I.e. you have WinXP image with 1vCPU/1GB, once you load it on a VM computer it will have exactly the resources you specified for the image (1vCPU/8GB).
I hope it helps.
On Feb 12, 2013, at 9:35 , "Basilio, Norvin" <nb...@odu.edu> wrote:
> Hello,
> I am curious on how others are configuring their VM computers. Right now I have configured groups of computers with ram configurations of 1GB, 2GB, 4GB, and 8GB. I've also grouped images the same way and mapped them to the corresponding computer groups. My problem with this method is that I have obviously limited the total numbers as it will not load 8GB vm computers with a 1GB image. I would like to know if I configure the the VM computers all as 8GB VM's will the vcl code stop any over provisioning the esxi hosts?
>
> Norvin Basilio
> Email: nbasilio@odu.edu
--
Thank you,
Dmitri Chebotarov
VCL Sys Eng, Engineering & Architectural Support, TSD - Ent Servers & Messaging
223 Aquia Building, Ffx, MSN: 1B5
Phone: (703) 993-6175 | Fax: (703) 993-3404
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Re: Question on how people are configuring their VM computers
Posted by Dmitri Chebotarov <dc...@gmu.edu>.
Hi Norvin
In our environment all VM computers configured with largest amount of resources (MEM, CPU) needed by an image.
I.e. if you have an image which needs 4 vCPU/8GB of memory then ALL VM computers would have4 vCPU and 8GB.
The VM computer configuration basically means 'up to' specified resources, it doesn't mean that all images will be loaded with max resources (4vCPU/8GB).
When you make a reservation/reload request for an image, it will be loaded on any VM computers which has adequate resources, but the image will be loaded with resources you specify for the image. I.e. you have WinXP image with 1vCPU/1GB, once you load it on a VM computer it will have exactly the resources you specified for the image (1vCPU/8GB).
I hope it helps.
On Feb 12, 2013, at 9:35 , "Basilio, Norvin" <nb...@odu.edu> wrote:
> Hello,
> I am curious on how others are configuring their VM computers. Right now I have configured groups of computers with ram configurations of 1GB, 2GB, 4GB, and 8GB. I've also grouped images the same way and mapped them to the corresponding computer groups. My problem with this method is that I have obviously limited the total numbers as it will not load 8GB vm computers with a 1GB image. I would like to know if I configure the the VM computers all as 8GB VM's will the vcl code stop any over provisioning the esxi hosts?
>
> Norvin Basilio
> Email: nbasilio@odu.edu
--
Thank you,
Dmitri Chebotarov
VCL Sys Eng, Engineering & Architectural Support, TSD - Ent Servers & Messaging
223 Aquia Building, Ffx, MSN: 1B5
Phone: (703) 993-6175 | Fax: (703) 993-3404