Normally, you can calculate the average number of VMs depends on the computing power (CPU). For example, 1 physical core can supports 2 VMs with 2 GB RAM. If you have 2 CPUs with 16 cores, then you might run 32VMs with 64GB RAM. However, the max number of VMs per host depends on variable facts as Al Quiros mentioned, In addition to Al's comments, you might also consider the application you want to run on guest VMs. If applications are more computation intensive, the number of CPUs would be important fact to decide the max number of VMs per host.
In our environment, we don't use VMware but running RHEL 6 x64 with KVM on IBM blade hosts with 16 CPUs and 24GB RAM. We run average 15 Windows XP VMs with 1GB memory without much performance overhead. However, we can run up to 22 VMs but the performance was not good. Best regards, -------------------------------------------------------------------- Young Hyun Oh IBM Tivoli From: Evelio Quiros <evq...@fiu.edu> To: "vcl-user@incubator.apache.org" <vcl-user@incubator.apache.org>, "'vcl-...@incubator.apache.org'" <vcl-...@incubator.apache.org>, Date: 05/24/2012 10:58 AM Subject: Re: Max Number of VMs per Host Hello, As you know, the number of Virtual Machines per host depends on available resources (CPU, RAM, Disk), as well as the demands of the image. As a general guide, I have found the following to be reasonable. Other admins, please share your opinions. For a single VM host with 12 virtual CPU and 98 GB RAM, I typically allocate 25 Windows VM. When necessary, I have raised it to 32 Windows XP machines. For linux based images, I have used 50 VM without issues. Monitor the performance tab on your vSphere client to see if the host is over-worked. On Virtual Machines that require higher performance, I usually will not place them on a host with more than 10 working VM. But the most important thing is to watch the performance closely. You will get a feel for how many VM per host by experience. As always, your mileage may vary. Regards, Al Quiros Florida International University From: <Sanders>, Arbin D <asand...@nccu.edu> Reply-To: "vcl-user@incubator.apache.org" <vcl-user@incubator.apache.org> Date: Wednesday, May 23, 2012 3:53 PM To: "'vcl-...@incubator.apache.org'" <vcl-...@incubator.apache.org>, " 'vcl-user@incubator.apache.org'" <vcl-user@incubator.apache.org> Subject: Max Number of VMs per Host All, What is the number of VMs do you all run per VMware host? Is it limited to the RAM limitation for vSphere 5? How many purchase vSphere licenses? Arbin Darren Sanders IT Manager – Academic Computing North Carolina Central University 712 Cecil Street Suite 3014 Durham, NC 27707 919.530.6307 919.530.5097 (Fax) For the Latest ITS Updates and Tips Join Us Online CONFIDENTIALITY: This email (including any attachments) may contain confidential, proprietary and privileged information, and unauthorized disclosure or use is prohibited. If you received this email in error, please notify the sender and delete this e-mail from your system. ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please visit http://www.symanteccloud.com ______________________________________________________________________
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