How to sizing how many VMware virtual machines can be hosted on a physical machine?
twt enterprise IT community 2018-05-18
From the community "VMware vSphere performance optimization design online Q&A" activity, questioner: sharkbing, answered by community experts
How to sizing how many vmware virtual machines can be hosted on a physical machine?
@chinesezzqiang A central enterprise
good question.
After the configuration of the virtual machine is determined, the configuration of the host can be obtained through simple calculations. The following is just an example:
For example, the memory of the virtual machine is 8G, and the CPU is 4 cores. Then the company estimates the total amount of 100 virtual machines (within 1 year), then it is recommended that each host has 25 virtual machines, 25*8=200G memory, and CPU is generally not the performance bottleneck of virtual machines. Reserve some memory for the system, so you can use 256G memory and 2 intel12core hosts. (Do not consider the needs of IO)
@chengzuqiao Jiangxi Rural Credit Cooperative
This should be allocated according to your application's use of resources, there is no certain standard, anyway, resources can be dynamically allocated
@Jerry Lee BRS CE
First, consider the performance efficiency of the ESX host, which is generally maintained at about 70% of the host performance pressure. The maximum is not recommended to exceed 85%.
Secondly, if you consider the balance between the number of ESX hosts and virtual machines, performance stress tests are generally performed before formal deployment, virtual machine templates of various production specifications are made, and stress test tools such as CPU/memory/disk IO are installed on the virtual machines. Increase the number of virtual machines of various sizes in batches until the ESX host reaches 70% and 85% performance.
Finally, if there are high availability or disaster tolerance requirements for the production ESX host, you need to evaluate the actual production pressure of the virtual machine before deploying the virtual machine, and then deploy it on the ESX that is under pressure.
@a520520168 Sofia
How much memory does the host have, and the total number of virtual machines must not exceed this number. This is for sure. . . . Then it must be reserved for the system or something. Generally it's OK. . . . The CPU counts the number of cores and threads. Overtake will compete. The network card and disk io will be observed.
Share several practical knowledge points of Vsphere HA
penguin23 twt enterprise IT community 2017-10-09
1. Host admission control strategy of Vsphere HA
It is divided into the number of hosts that allow failures, the percentage of resource reservations, designated failover hosts, and unreserved resources.
Because each HOST in Vsphere HA may be responsible for restarting the HOST to switch over at any time. Generally, the next HOST configuration of different VM Failover will be considered.
A. Specify the number of failed hosts: Reserve resources of the host for important VMs.
B. Resource reservation percentage: Reserve the entire Cluster resource in percentage. For example, all the host memory of the host in the cluster is 220G, and the reserved 10% is 22G.
C. Specify the failover host, because a host is required to be in a stand by state all the time.
D. No resources are reserved.
2. By setting the weight of VMs, important VMs can obtain reserved resources.
Note that when two hosts in the Cluster are down, he will start the VM on the first host first, and will start the VM on the second host after the startup is complete, despite the weight of the VM on the second host It may be higher than the one on the first host.
Find OUT: Which is the first Host in the Cluster.
3. Personal summary on the standard switch and distributed switch of the Vsphere host;
A. The standard switch can be configured to create the same corresponding Vlan network as the distributed switch.
B. Configure Vmkernel separately with standard switches to avoid trouble when deleting distributed switches.
4. Reset Esxi host, reset root password, reset Esxi Host network configuration.