ESXi 5.5 U2 installed on HP Blade (Core allocation per VM)

[vickyshiv123]

Hi,

Could anyone of you please help on the below queries

• ESXi 5.5 U2 Installed on HP Blade (Total capacity of RAM- 128GB and no of CPUS- 16  per blade )
• VMs configured on ESXi 5.5 U2 with 8GB RAM-->1 vCPU (per VM), for eg: if total 16 vCPUs has been utilized by the VMs, will it be possible to configure anymore VMs or do we need to add more physical and then configure vCPUs for VMs, I have one client running ESXi hosts with 16 physical CPUs but the total vCPUs configured is 17 and it is running fine until now, Just wondering vCPUs allocation of the VMs depends on the physical CPUs of the ESXi hosts then how it would be able to allocate more vCPUS, kindly advise on this and moreover whether this can be followed as a best practice. (vCPUs allocation is static right or is that any option for dynamic vCPU allocation?)
• One more more query regarding core allocation, our sales person somehow told me that vCPUs for VMs can be allocated as quarter core or even half core so we could able to have more cores in a blade regardless of increasing the physical CPUs on the blade, as far as my understanding there is no such option available in both VMware vSphere or in VMware vCloud Automation center (VCAC), if in case there is any option available to configure kindly instruct on this.

Much appreciate your reply and looking forward for your response.

Thanks

Vick

[Techie01]

Hi Vick

>>

• VMs configured on ESXi 5.5 U2 with 8GB RAM-->1 vCPU (per VM), for eg: if total 16 vCPUs has been utilized by the VMs, will it be possible to configure anymore VMs or do we need to add more physical and then configure vCPUs for VMs, I have one client running ESXi hosts with 16 physical CPUs but the total vCPUs configured is 17 and it is running fine until now, Just wondering vCPUs allocation of the VMs depends on the physical CPUs of the ESXi hosts then how it would be able to allocate more vCPUS, kindly advise on this and moreover whether this can be followed as a best practice. (vCPUs allocation is static right or is that any option for dynamic vCPU allocation?)

>>

I assume your questions as ,  you have 16PCPU esx and you want to power on more than 16 VM's and each VM has 1 vCPU.   If that is the question, then you can have definitely more than 16VM's.  As per max guide, you can have upto 512 VMs in 5.5 . But note that, this number is based certain assumption and the practically meaningful number could be much less. But definitely far more than 16.

>>

• One more more query regarding core allocation, our sales person somehow told me that vCPUs for VMs can be allocated as quarter core or even half core so we could able to have more cores in a blade regardless of increasing the physical CPUs on the blade, as far as my understanding there is no such option available in both VMware vSphere or in VMware vCloud Automation center (VCAC), if in case there is any option available to configure kindly instruct on this.

>>

Just like physical machine, the vm process are scheduled on per core. The process cannot be scheduled on quarter core or half core. I believe the sales person is trying to explain something different ( may be about features like HT ).

I would recommend you to read some technical resources in vmware.com ( such as https://www.vmware.com/files/pdf/techpaper/VMware-vSphere-CPU-Sched-Perf.pdf)

[vickyshiv123]

Hi,

Thanks for your response.

Can I conclude, even though vCPUs has been reserved statically, it can dynamically shares or use the vCPUs depending on the CPU resource utilization.

For eg: suppose the ESXi hosts has the capacity of PCPUs(16) and the total vCPUs allocated for the VMs is 16vCPUs  but still if we want to configure a new VM with 2vCPUs , so all together (16 vCPUs +2 vCPUs= 18 vCPUs against to 16PCPUS), this can do configured right?

Kindly confirm on the above

Vick

[Techie01]

Exactly. That is the benefit of virtualization . You can have more total vcpu than pcpus.

There are lot of documents which mentions how many VM's per server is recommended.( such as this link Max amount of VMs per Host? - Yellow Bricks   )

[vickyshiv123]

Hi

Thank you so much for your confirmation.

One more clarification

We have installed  two new Broadcom Netxtreme I Dual port Gigabit Ethernet NIC adapter on IBM x3650 M3 server, the thing here is we could able to see the NIC adapter on the server bios level but not able to see on the ESXi host. FYI,  ESXi 5.0 (Essential) is installed on this server, no update manager in the environment. My query.is

1. Do we need to any driver on the esxi host level inorder to detect the nic adapters, if its yes what driver need to be installed.and how ?

2. On other end, the server nic port is connected to the Network switch, any configuration needs to be done on the switch level (vlan)?

Kindly advise on the above ones

Much appreciate your help.

Thanks

Vick