Azure regularly retires older virtual machine (VM) series, and if you ignore these changes, your workloads can face performance issues, security risks, or even service disruption. Migrating to the latest-generation VMs ensures better speed, improved networking, and long-term support.
This guide shows you exactly how to migrate retiring Azure VMs step by step without losing data or causing major downtime.
Why You Must Migrate Retiring Azure VMs
Azure does not keep older VM hardware forever. When Microsoft retires a VM series, it gradually removes support and limits availability.
If you delay migration, you may face:
- Unexpected downtime
- Reduced performance
- Unsupported configurations
- Forced migration by Azure
New VM generations (v6, v7) deliver higher CPU performance, better networking, and improved price efficiency. Migrating early keeps your infrastructure stable and future-ready.
Step 1: Identify Retiring Virtual Machines
Start by finding which VMs need migration.
Do this:
- Open Azure Portal
- Go to Virtual Machines
- Check the VM Size column
- Look for retirement alerts
You can also use:
- Azure Advisor → shows upgrade recommendations
- Azure Migrate → shows dependencies and inventory
This step helps you avoid breaking connected services during migration.
Step 2: Choose the Right Latest-Generation VM
Do not blindly upgrade. Choose a VM that matches your workload.
Check these before selecting a new VM:
- vCPU and RAM requirements
- Disk type (Standard, Premium SSD, Ultra Disk)
- Accelerated networking support
- Region availability
Simple upgrade examples:
- Dv2: Dv5 or Dv7
- A-series: B-series or Dsv6
- F-series: Fsv2 or Fasv7
Always right-size your VM instead of copying the same specs.
Step 3: Take Backup or Snapshot
Before making changes, protect your data.
Do this:
- Go to Disks → Create Snapshot
- Or create a full VM backup
This ensures you can recover quickly if anything goes wrong.
Step 4: Stop and Deallocate the VM
Azure does not allow resizing while the VM runs.
Steps:
- Open VM → Click Stop (Deallocate)
- Wait until status shows Stopped (Deallocated)
Do not skip this step.
Step 5: Resize the VM (Quick Method)
If the new VM size is available in the same region, resizing is the fastest method.
Steps:
- Go to VM → Size
- Select new VM (example: D4s_v5 or Dsv6)
- Click Resize
CLI option (for automation):
az vm deallocate --resource-group MyRG --name MyVM
az vm resize --resource-group MyRG --name MyVM --size Standard_D4s_v5
az vm start --resource-group MyRG --name MyVMUse CLI when you manage multiple VMs or automate deployments.
Step 6: Redeploy the VM When Resize Is Not Available
If the new VM size does not appear in the list, Azure is restricting it on the current hardware cluster.
Use Redeploy to fix this:
- Go to your VM in Azure Portal
- Click Redeploy + Reapply
- Confirm the action
Azure moves your VM to a new physical host. This process does not change your configuration, but it refreshes the underlying hardware allocation.
Important:
- Redeploy causes a short downtime
- Your IP address may change if not static
- After redeploy, try resizing again
If the size still does not appear, move to snapshot-based migration.
Step 7: Use Snapshot + New VM (Reliable Method)
This method works for all cases and avoids compatibility issues.
Steps:
- Create snapshot of OS disk
- Create new VM using that snapshot
- Select latest VM generation (v6/v7)
- Attach data disks
- Configure networking
This method gives you a clean environment.
Step 8: Use Azure Site Recovery (Zero Downtime Option)
For production workloads, use Azure Site Recovery.
What it does:
- Replicates your VM continuously
- Lets you fail over to a new VM with minimal downtime
This method works best for:
- Critical applications
- High-traffic systems
Step 9: Validate the New VM
After migration, verify that your VM works correctly under real conditions.
Check these metrics using Azure Monitor:
- CPU usage: ensure no unexpected spikes
- Memory utilization: confirm proper sizing
- Disk latency: check read/write performance
- Network throughput: verify connectivity stability
Also test:
- Application response time
- API endpoints
- Database connections
Run your workload for a few hours under normal traffic before moving forward.
Step 10: Decommission the Old VM
Do not delete your old VM immediately.
Follow this approach:
- Keep the old VM stopped for 3–7 days
- Monitor the new VM for stability
- Confirm no missing data or configuration
Once everything works correctly:
- Delete old VM
- Remove unused disks
- Clean up snapshots
This step avoids rollback issues and reduces unnecessary storage costs.
Best VM Series to Choose (2026)
Use this quick guide:
- General workloads: Dsv6 or Dasv7
- Memory-heavy apps: Easv7
- Compute-intensive: Fasv7
- AI/ML: ND v6 (GPU)
- Budget/dev: B-series
Latest-generation VMs offer better performance and cost efficiency.
Common Mistakes to Avoid
Avoid these errors during migration:
- Skipping backup
- Choosing wrong VM size
- Ignoring disk compatibility
- Not testing after migration
- Deleting old VM too early
These mistakes can cause downtime or data issues.
FAQs: Migrate Azure Virtual Machines
How do I migrate Azure Virtual Machines to a new VM generation?
To migrate Azure Virtual Machines, stop (deallocate) the VM, select a new supported VM size, and resize it. If resizing is not available, use snapshot-based migration or Azure Site Recovery.
Can I upgrade Azure VM without losing data?
Yes, you can upgrade an Azure VM without losing data if you resize the VM correctly or migrate using snapshots. Always take a backup before starting.
What happens if Azure VM is not migrated after retirement?
If you do not migrate, Azure may restrict VM operations, reduce performance, or eventually stop the VM from running due to unsupported hardware.
What is the easiest way to migrate Azure Virtual Machines?
The easiest method is in-place resize. Stop the VM, choose a new VM size, and apply the change if the size is available in your region.
When should I use Azure Site Recovery for migration?
Use Azure Site Recovery when you need near-zero downtime. It continuously replicates your VM and allows smooth failover to a new VM generation.
Why is my new Azure VM size not showing during resize?
The new VM size may not appear due to region limitations or hardware constraints. Use the redeploy option or migrate the VM using snapshots.
Which Azure VM generation should I choose in 2026?
You should choose v6 or v7 VM series. They provide better CPU performance, improved networking, and higher cost efficiency compared to older generations.
Is downtime required when migrating Azure Virtual Machines?
Yes, resizing requires downtime because you must stop the VM. However, Azure Site Recovery can reduce downtime significantly.
How long does Azure VM migration take?
Simple resizing takes a few minutes. Snapshot-based migration may take longer depending on disk size and configuration.
What are the common mistakes during Azure VM migration?
Common mistakes include skipping backups, choosing the wrong VM size, ignoring compatibility checks, and deleting the old VM too early.
Can I migrate Azure VM to another region during upgrade?
Yes, you can migrate to another region by creating a snapshot or image and deploying a new VM in the target region.
Does upgrading Azure VM improve performance?
Yes, latest-generation Azure VMs offer faster CPUs, better networking, and improved storage performance, which significantly enhances workload efficiency.
Migrating retiring Azure VMs is a controlled upgrade, not just a maintenance task. When you act early, you avoid forced downtime and gain better performance from modern VM generations. The process becomes simple when you follow a clear path—identify affected VMs, choose the right size, migrate using the correct method, and validate everything before cleanup.
Latest-generation VMs like v6 and v7 deliver strong improvements in speed, networking, and cost efficiency. If your VM shows a retirement notice, do not delay. Complete the migration now and keep your infrastructure stable, supported, and ready for future workloads.
