Review isolation retirement separately from whether an Azure VM size still runs

Source facts

Azure isolated VM sizes are tied to specific hardware generations and have a limited hardware lifetime. Microsoft distinguishes retirement of isolation from retirement of the size: unless stated otherwise, an isolated size without an “i” in its name can lose only the isolation feature, while sizes containing “i” are retired entirely. Where only isolation ends, the source says the transition requires no action or downtime; retaining isolation requires moving to a replacement size. Microsoft Learn.

Applicability

Use this review when an architecture depends on a VM being the only VM on its physical server. Confirm the exact size and retirement announcement rather than interpreting its current running state as continuing evidence of the desired isolation. Keep regulatory interpretation outside this technical inventory.

DSE recommendation

Track the isolation retirement notice as a workload design change even when the VM size itself remains usable. Ask the workload and security owners whether the original isolation requirement still applies. If it does, select a currently supported replacement and approve its migration plan before the stated retirement boundary. Keep continued operation and continued isolation as separate acceptance questions.

Verification

Compare the deployed size with the current isolated-size listing and its specific announcement. For an approved replacement, verify the resulting size and test workload capacity and operation. Retain the reason for migration, relevant deadline, and final deployment identity. An application that continues responding after a retirement date should not by itself close the review of the physical-isolation requirement.

Official references

Microsoft Learn: Virtual machine sizes that provide isolation in Azure. Source reviewed September 9, 2026.