VM reservation

Question

HI..

we have 4 VM Standard_E4-2s_v3 and each VM have 2 vCPUs and 32GB Memory.
When i want to purchase reservation why for this kind of VM the vCPUs is 4 not 2?

Answer 1

Hello @Handian Sudianto ,
Welcome to Microsoft QnA.
Standard E4_2S_v3 VM is a constrained vCPU capable VM and it has the following specifications:
Standard is recommended tier
E – Optimised for in-memory hyper-threaded applications
4 – The number of vCPUs
2 – The actual number of vCPUs for the constrained vCPU capable size.
Reduces the cost of software licensing, while maintaining the same memory, storage, and I/O bandwidth.
s – Premium Storage capable
v3 – version

Therefore, it is showing correctly as the available vCPU count can be reduced to one half or one quarter of the original VM specification. These new VM sizes have a suffix that specifies the number of available vCPUs to make them easier for you to identify. There are no additional cores available that can be used by the VM.

For more details on what are constrained vCPU capable VMs, please refer to this document : https://learn.microsoft.com/en-us/azure/virtual-machines/constrained-vcpu

Hope this helps. Feel free to reach back if you have any questions.

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Answer 2

Hello @Handian Sudianto

Please refer document section reserved-vm-instance-size-flexibility for more details along with instance flexibility ratio chart which will give you clarity on this. In this case, you can try toggle optimize for instance flexibility (preview) option and see if there is a difference in recommendation.

Regards,
Divya.

Answer 3

Hi,

This is one of the Constrained vCPU SKUs. For compute you are charged for the underlying vCPU count (4 in this case), whereas for SQL Server licensing purposes you are charged based on the Active vCPU count (2). Below is quote from https://azure.microsoft.com/en-us/pricing/details/virtual-machines/windows/#pricing:

These new VM sizes are optimized for database workloads like SQL Server that often require high memory, storage, and I/O bandwidth, but not a high CPU core count. They constrain the VM vCPU(s) count and can help reduce the cost of software licensing, all while maintaining the same memory, storage, and I/O bandwidth. The licensing charged for SQL Server will be constrained to the active vCPU(s) count while the compute cost, which includes OS licensing, remains the same one as the original size based on “underlying vCPU(s)”. These new VM sizes allow customer workloads to use the same memory, storage, and I/O bandwidth while optimizing their software licensing cost.

-TP