Moving Vm's to a new reservation

pierre shiraziefard 165 Reputation points
2026-07-10T14:12:07.32+00:00

Hello, this is what I have currently looking for a solution:

standard_B4ms North Central US

standard_B4ms South Central US (stopped currently)

both above on pay as you go subscription

B4ms is not available in Chicago North Central but a replacement Basv2 is available same specs.

Question, how do I move the existing B4ms to a new purchased reservation with a Basv2?

Do i have to load all software on a new VM or is there a way to transfer from one machine to another?

I am trying to eliminate a manual re-installation of our software components. I also want to make sure the new reserved VM I stand up will use 100% of the reserved resources.

Thanks.

Azure Virtual Machines
Azure Virtual Machines

An Azure service that is used to provision Windows and Linux virtual machines.

Answer accepted by question author
Sina Salam 31,456 Reputation points Volunteer Moderator
2026-07-13T13:13:07.7933333+00:00

Hello pierre shiraziefard,

Welcome to the Microsoft Q&A and thank you for posting your questions here.

I understand that you would like moving VMs to a new reservation.

Moving your current Pay-As-You-Go Standard_B4ms VM workload to a new Standard_B4as_v2 Reserved VM Instance without manually reinstalling applications, and you also want the reserved resources to be fully utilized. Know this that an Azure Reserved VM Instance does not contain or host a VM. It is only a billing discount that automatically applies to matching running VM compute usage based on the reservation’s region, scope, VM size/flexibility group, and quantity. You do not move a VM into a reservation; instead, you must run the VM on a SKU that matches the reservation. - https://learn.microsoft.com/en-us/azure/virtual-machines/prepay-reserved-vm-instances, and https://learn.microsoft.com/en-us/azure/virtual-machines/reserved-vm-instance-size-flexibility gives more insight.

What you can do is to:

  • First, resize the existing Standard_B4ms VM to Standard_B4as_v2 - (subjected to normal resize requirements).
  • If direct resize is not available or fails, recreate the VM from the existing managed OS disk or snapshot so the installed applications remain intact.
  • Validate the VM runs correctly as Standard_B4as_v2.
  • Only then purchase the Standard_B4as_v2 reservation in the same region and scope.
  • Confirm reservation utilization after purchase.

This avoids unnecessary reinstalling and ensures the reservation is only purchased after the target VM size is confirmed to be usable.

Use the below Microsoft resources for more reading and steps:

I hope this is helpful. Please! Do not hesitate to let me know if you have any other questions, steps or clarifications.

Please do not close the thread by upvoting and accepting the answer if any part of it is helpful.

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  1. pierre shiraziefard 165 Reputation points
    2026-07-13T22:16:06.43+00:00

    from reservations it allows you to buy anything close to my requirements b4as, yet none are available when I try to create in any of zone 1 through zone 3 and as a result I do not want to pay for a reservation if I am not able to deploy the vm. how best to tackel this? ideally i should be able to see availability while I am purchaisng a reservation? it allows to purchase any reservation yet I am not able to locate the cpu matching family class on the region or zone.

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  2. pierre shiraziefard 165 Reputation points
    2026-07-13T22:15:24.8666667+00:00

    from reservations it allows you to buy anything close to my requirements b4as, yet none are available when I try to create in any of zone 1 through zone 3 and as a result I do not want to pay for a reservation if I am not able to deploy the vm. how best to tackel this? ideally i should be able to see availability while I am purchaisng a reservation? it allows to purchase any reservation yet I am not able to locate the cpu matching family class on the region or zone.

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  3. Christos Panagiotidis 3,551 Reputation points
    2026-07-13T12:40:49.9333333+00:00

    Hi! A Reserved VM Instance is a billing discount, not a separate VM, so you normally do not reinstall the operating system or applications. Deallocate the existing VM and resize it to a compatible Basv2 SKU; its OS and data disks remain intact. The reservation benefit will apply automatically only when the running VM matches the reservation’s region, scope, and instance-size flexibility group. Confirm compatibility before purchasing. Microsoft documents the resize process and instance-size flexibility.

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  4. Nikhil Duserla 9,950 Reputation points Microsoft External Staff Moderator
    2026-07-10T14:24:18.2233333+00:00

    Hello @pierre shiraziefard ,

    Since Standard_B4ms and Standard_B4as_v2 belong to different VM size families, an existing Reserved VM Instance (RI) purchased for B4ms cannot be applied to a B4as_v2 VM.

    To migrate your workload from B4ms to B4as_v2 while preserving the operating system and application configuration:

    1. Create a managed image or snapshot of the existing B4ms VM.
    2. Deploy a new Standard_B4as_v2 VM using the captured image.
    3. The new VM will retain the same operating system, installed applications, and configuration as the source VM.
    4. Reconfigure any networking components (public/private IP addresses, DNS records, Network Security Groups, Load Balancer backend pools, etc.) as required.
    5. Validate application functionality and performance on the new VM.
    6. After successful validation, decommission the original B4ms VM.

    Also, Detach and reattach data disks: If application data resides on separate managed disks, attach those disks to the newly deployed VM after deployment.

    Before purchasing the reservation and migrating the workload, verify that:

    • Standard_B4as_v2 is available in the North Central US region.
    • The CPU, memory, and performance characteristics of B4as_v2 meet your application's requirements.

    Let me know if you have any further queries.

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