Convert your OS disks on Standard HDD to Standard SSD or Premium SSD before 8 September 2028. Will automatic conversion after this date have downtime?

Sergio Antunes 0 Reputation points
2026-10-23T11:46:15.02+00:00

Convert your OS disks on Standard HDD to Standard SSD or Premium SSD before 8 September 2028. Will automatic conversion after this date have downtime?

In order to convert an attached Standard HDD disk to Standard SSD or Premium SSD, virtual machine or virtual machines scale sets need to be deallocated to be converted. Will the automatic converstion after 8 September imply downtime if virtual machines are running?

Azure Storage
Azure Storage

Globally unique resources that provide access to data management services and serve as the parent namespace for the services.

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  1. Hassan Nazeer 0 Reputation points
    2026-10-23T12:13:21.4+00:00

    I'd plan for downtime. Microsoft hasn't documented the automatic conversion as a no-reboot operation. The retirement page only says that after 8 September 2028 the remaining Standard HDD OS disks are converted to Standard SSD of equivalent size, and that workloads "may experience a service disruption" if they weren't migrated first. That wording is the reason to convert on your own schedule.

    What is documented today:

    • Changing a managed disk type needs the VM stopped (deallocated). Learn says to schedule it in a maintenance window because it requires a restart. The type change itself is instantaneous, so the downtime is mostly the stop and start.
    • Only OS disks are in scope. Standard HDD data disks, snapshots and Standard HDD OS disks created by Azure Site Recovery are not affected.

    What I would do:

    1. List the affected disks (command from the retirement page): az disk list --query "[?sku.name=='Standard_LRS' && osType!=null]" --output table
    2. Per VM: take a snapshot, deallocate, change the OS disk to StandardSSD_LRS (portal: VM > Disks > disk > Size + performance > Account type, or az disk update --sku StandardSSD_LRS), then start the VM.
    3. Verify with az disk show -g <rg> -n <disk> --query sku.name, which should return StandardSSD_LRS.
    4. For VMs behind a load balancer or in an availability set, do them one at a time so the service stays up.

    Limits: you can change a disk's type only twice per day. Premium SSD needs a VM size that supports premium storage, while Standard SSD doesn't. I haven't tested scale set instances, and the convert page's steps are written for individual VMs, so test one instance first. If you need a formal statement on how the automatic conversion will run, raise it through Azure support.

    Sources:

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